Fixes:

```
panic: Panicked on a Sanity Check: can't encode times below 1970 [recovered]
        panic: Panicked on a Sanity Check: can't encode times below 1970

goroutine 2042 [running]:
testing.tRunner.func1(0xc420e8c0f0)
        /usr/local/go/src/testing/testing.go:711 +0x5d9
panic(0xcd9e20, 0xc420c8c270)
        /usr/local/go/src/runtime/panic.go:491 +0x2a2
github.com/tendermint/tendermint/vendor/github.com/tendermint/tmlibs/common.PanicSanity(0xcd9e20, 0xf8ddd0)
        /go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/tmlibs/common/errors.go:26 +0x120
github.com/tendermint/tendermint/vendor/github.com/tendermint/go-wire.WriteTime(0x0, 0x0, 0x0, 0x1306440, 0xc4201607e0, 0xc420e31658, 0xc420e31680)
        /go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/go-wire/time.go:19 +0x11e
github.com/tendermint/tendermint/vendor/github.com/tendermint/go-wire.writeReflectBinary(0xdc9e40, 0xc4201fcf30, 0x199, 0x1317b80, 0xdc9e40, 0xc98451, 0x9, 0x0, 0xdc9e40, 0xc420ead9c0, ...)
        /go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/go-wire/reflect.go:525 +0x22f0
github.com/tendermint/tendermint/vendor/github.com/tendermint/go-wire.writeReflectBinary(0xd25400, 0xc42000e2e8, 0x196, 0x1317b80, 0xd92d60, 0xc9a195, 0xa, 0x0, 0xcc8ce0, 0xc420164920, ...)
        /go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/go-wire/reflect.go:530 +0x21e7
github.com/tendermint/tendermint/vendor/github.com/tendermint/go-wire.writeReflectBinary(0xcc8ce0, 0xc4209f95b8, 0x197, 0x1317b80, 0xcc8ce0, 0xc9a195, 0xa, 0x0, 0xcc8ce0, 0xc420164920, ...)
        /go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/go-wire/reflect.go:518 +0x2509
github.com/tendermint/tendermint/vendor/github.com/tendermint/go-wire.writeReflectBinary(0xd873e0, 0xc4209f9580, 0x16, 0x1317b80, 0xd79400, 0x0, 0x0, 0x0, 0x0, 0x0, ...)
        /go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/go-wire/reflect.go:530 +0x21e7
github.com/tendermint/tendermint/vendor/github.com/tendermint/go-wire.WriteBinary(0xd873e0, 0xc4209f9580, 0x1306440, 0xc4201607e0, 0xc420e31658, 0xc420e31680)
        /go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/go-wire/wire.go:80 +0x15f
github.com/tendermint/tendermint/vendor/github.com/tendermint/go-wire.BinaryBytes(0xd873e0, 0xc4209f9580, 0x3, 0x8, 0xc420160798)
        /go/src/github.com/tendermint/tendermint/vendor/github.com/tendermint/go-wire/util.go:15 +0xb8
github.com/tendermint/tendermint/blockchain.(*BlockStore).SaveBlock(0xc4201342a0, 0xc420eac180, 0xc420130640, 0xc4209f9580)
        github.com/tendermint/tendermint/blockchain/_test/_obj_test/store.go:192 +0x439
github.com/tendermint/tendermint/blockchain.TestBlockStoreSaveLoadBlock(0xc420e8c0f0)
        /go/src/github.com/tendermint/tendermint/blockchain/store_test.go:128 +0x609
testing.tRunner(0xc420e8c0f0, 0xf20830)
        /usr/local/go/src/testing/testing.go:746 +0x16d
created by testing.(*T).Run
        /usr/local/go/src/testing/testing.go:789 +0x569
exit status 2
FAIL
```

Update state to keep track of this info.
Change function args as needed.
Make NumTx also an int64 for consistency.

With feedback from @ebuchman, to make the tests nicer
and less fragile.

Add tests to test store, to the fullest reasonable extent for
paths that can taken by input arguments altering internal behavior,
as well as by mutating content in the DB.

uint64 is considered dangerous. the details will follow in a blog post.

See https://github.com/tendermint/tmlibs/issues/45

comment out failing consensus tests for now

rewrite rpc httpclient to use new pubsub package

import pubsub as tmpubsub, query as tmquery

make event IDs constants
EventKey -> EventTypeKey

rename EventsPubsub to PubSub

mempool does not use pubsub

rename eventsSub to pubsub

new subscribe API

fix channel size issues and consensus tests bugs

refactor rpc client

add missing discardFromChan method

add mutex

rename pubsub to eventBus

remove IsRunning from WSRPCConnection interface (not needed)

add a comment in broadcastNewRoundStepsAndVotes

rename registerEventCallbacks to broadcastNewRoundStepsAndVotes

See https://dave.cheney.net/2014/03/19/channel-axioms

stop eventBuses after reactor tests

remove unnecessary Unsubscribe

return subscribe helper function

move discardFromChan to where it is used

subscribe now returns an err

this gives us ability to refuse to subscribe if pubsub is at its max
capacity.

use context for control overflow

cache queries

handle err when subscribing in replay_test

rename testClientID to testSubscriber

extract var

set channel buffer capacity to 1 in replay_file

fix byzantine_test

unsubscribe from single event, not all events

refactor httpclient to return events to appropriate channels

return failing testReplayCrashBeforeWriteVote test

fix TestValidatorSetChanges

refactor code a bit

fix testReplayCrashBeforeWriteVote

add comment

fix TestValidatorSetChanges

fixes from Bucky's review

update comment [ci skip]

test TxEventBuffer

update changelog

fix TestValidatorSetChanges (2nd attempt)

only do wg.Done when no errors

benchmark event bus

create pubsub server inside NewEventBus

only expose config params (later if needed)

set buffer capacity to 0 so we are not testing cache

new tx event format: key = "Tx" plus a tag {"tx.hash": XYZ}

This should allow to subscribe to all transactions! or a specific one
using a query: "tm.events.type = Tx and tx.hash = '013ABF99434...'"

use TimeoutCommit instead of afterPublishEventNewBlockTimeout

TimeoutCommit is the time a node waits after committing a block, before
it goes into the next height. So it will finish everything from the last
block, but then wait a bit. The idea is this gives it time to hear more
votes from other validators, to strengthen the commit it includes in the
next block. But it also gives it time to hear about new transactions.

waitForBlockWithUpdatedVals

rewrite WAL crash tests

Task:
test that we can recover from any WAL crash.

Solution:
the old tests were relying on event hub being run in the same thread (we
were injecting the private validator's last signature).

when considering a rewrite, we considered two possible solutions: write
a "fuzzy" testing system where WAL is crashing upon receiving a new
message, or inject failures and trigger them in tests using something
like https://github.com/coreos/gofail.

remove sleep

no cs.Lock around wal.Save

test different cases (empty block, non-empty block, ...)

comments

add comments

test 4 cases: empty block, non-empty block, non-empty block with smaller part size, many blocks

fixes as per Bucky's last review

reset subscriptions on UnsubscribeAll

use a simple counter to track message for which we panicked

also, set a smaller part size for all test cases

https://github.com/tendermint/tendermint/issues/762#issuecomment-338276055
```
E[10-19|04:52:38.969] Stopping peer for error                      module=p2p peer="Peer{MConn{178.62.46.14:46656} B14916FAF38A out}" err="Error: runtime error: invalid memory address or nil pointer dereference\nStack: goroutine 529485 [running]:\nruntime/debug.Stack(0xc4355cfb38, 0xb463e0, 0x11b1c30)\n\t/usr/local/go/src/runtime/debug/stack.go:24 +0xa7\ngithub.com/cosmos/gaia/vendor/github.com/tendermint/tendermint/p2p.(*MConnection)._recover(0xc439a28870)\n\t/home/ubuntu/go/src/github.com/cosmos/gaia/vendor/github.com/tendermint/tendermint/p2p/connection.go:206 +0x6e\npanic(0xb463e0, 0x11b1c30)\n\t/usr/local/go/src/runtime/panic.go:491 +0x283\ngithub.com/cosmos/gaia/vendor/github.com/tendermint/tendermint/blockchain.(*bpPeer).decrPending(0x0, 0x381)\n\t/home/ubuntu/go/src/github.com/cosmos/gaia/vendor/github.com/tendermint/tendermint/blockchain/pool.go:376 +0x22\ngithub.com/cosmos/gaia/vendor/github.com/tendermint/tendermint/blockchain.(*BlockPool).AddBlock(0xc4200e4000, 0xc4266d1f00, 0x40, 0xc432ac9640, 0x381)\n\t/home/ubuntu/go/src/github.com/cosmos/gaia/vendor/github.com/tendermint/tendermint/blockchain/pool.go:215 +0x139\ngithub.com/cosmos/gaia/vendor/github.com/tendermint/tendermint/blockchain.(*BlockchainReactor).Receive(0xc42050a780, 0xc420257740, 0x1171be0, 0xc42ff302d0, 0xc4384b2000, 0x381, 0x1000)\n\t/home/ubuntu/go/src/github.com/cosmos/gaia/vendor/github.com/tendermint/tendermint/blockchain/reactor.go:160 +0x712\ngithub.com/cosmos/gaia/vendor/github.com/tendermint/tendermint/p2p.createMConnection.func1(0x11e5040, 0xc4384b2000, 0x381, 0x1000)\n\t/home/ubuntu/go/src/github.com/cosmos/gaia/vendor/github.com/tendermint/tendermint/p2p/peer.go:334 +0xbd\ngithub.com/cosmos/gaia/vendor/github.com/tendermint/tendermint/p2p.(*MConnection).recvRoutine(0xc439a28870)\n\t/home/ubuntu/go/src/github.com/cosmos/gaia/vendor/github.com/tendermint/tendermint/p2p/connection.go:475 +0x4a3\ncreated by github.com/cosmos/gaia/vendor/github.com/tendermint/tendermint/p2p.(*MConnection).OnStart\n\t/home/ubuntu/go/src/github.com/cosmos/gaia/vendor/github.com/tendermint/tendermint/p2p/connection.go:170 +0x187\n"
```

```
jaekwon
Yeah we should definitely expose ChainID.
ConsensusParams is small enough, we can just write it.
```
https://github.com/tendermint/tendermint/pull/676#discussion_r144123203

- remove state#GenesisDoc() method

Fixes #671

Unexpose GenesisDoc and ChainID fields to avoid them being
serialized to the DB on every block write/state.Save()

A GenesisDoc can now be alternatively written to the state's
database, by serializing its JSON as a value of key "genesis-doc".

There are now accessors and a setter for these attributes:
- state.GenesisDoc() (*types.GenesisDoc, error)
- state.ChainID() (string, error)
- state.SetGenesisDoc(*types.GenesisDoc)

This is a breaking change since it changes how the state's
serialization and requires that if loading the GenesisDoc entirely
from the database, you'll need to set its value in the database
as the GenesisDoc's JSON marshaled bytes.

Fixes #514
Replaces #540

If a peer requests a block with a height that we don't have
respond with a bcNoBlockResponseMessage.
However, according to the Tendermint spec, if all nodes are honest
this condition shouldn't occur, so this is a possible hint of an
dishonest node.