Refs #986

* fix docs for vue, #1640

* docs: clean up re-install instructions

Memory leak in Websocket

* Switch from xchachapoly to hkdfchachapoly

Refs #1755

I started with writing a test for wsConnection (WebsocketManager) where
I:

- create a WS connection
- do a simple echo call
- close it

No leaking goroutines, nor any leaking memory were detected.

For useful shortcuts see my blog post
https://blog.cosmos.network/debugging-the-memory-leak-in-tendermint-210186711420

Then I went to the rpc tests to see if calling Subscribe results in
memory growth. It did.

I used a slightly modified version of TestHeaderEvents function:

```
func TestHeaderEvents(t *testing.T) {
	// memory heap before
	f, err := os.Create("/tmp/mem1.mprof")
	if err != nil {
		t.Fatal(err)
	}
	pprof.WriteHeapProfile(f)
	f.Close()

	for i := 0; i < 100; i++ {
		c := getHTTPClient()
		err = c.Start()
		require.Nil(t, err)

		evtTyp := types.EventNewBlockHeader
		evt, err := client.WaitForOneEvent(c, evtTyp, waitForEventTimeout)
		require.Nil(t, err)
		_, ok := evt.(types.EventDataNewBlockHeader)
		require.True(t, ok)

		c.Stop()
		c = nil
	}

	runtime.GC()

	// memory heap before
	f, err = os.Create("/tmp/mem2.mprof")
	if err != nil {
		t.Fatal(err)
	}
	pprof.WriteHeapProfile(f)
	f.Close()

	// dump all running goroutines
	time.Sleep(10 * time.Second)
	pprof.Lookup("goroutine").WriteTo(os.Stdout, 1)
}
```

```
Showing nodes accounting for 35159.16kB, 100% of 35159.16kB total
Showing top 10 nodes out of 48
      flat  flat%   sum%        cum   cum%
32022.23kB 91.08% 91.08% 32022.23kB 91.08%  github.com/tendermint/tendermint/libs/pubsub/query.(*QueryParser).Init
 1056.33kB  3.00% 94.08%  1056.33kB  3.00%  bufio.NewReaderSize
  528.17kB  1.50% 95.58%   528.17kB  1.50%  bufio.NewWriterSize
  528.17kB  1.50% 97.09%   528.17kB  1.50%  github.com/tendermint/tendermint/consensus.NewConsensusState
  512.19kB  1.46% 98.54%   512.19kB  1.46%  runtime.malg
  512.08kB  1.46%   100%   512.08kB  1.46%  syscall.ByteSliceFromString
         0     0%   100%   512.08kB  1.46%  github.com/tendermint/tendermint/consensus.(*ConsensusState).(github.com/tendermint/tendermint/consensus.defaultDecideProposal)-fm
         0     0%   100%   512.08kB  1.46%  github.com/tendermint/tendermint/consensus.(*ConsensusState).addVote
         0     0%   100%   512.08kB  1.46%  github.com/tendermint/tendermint/consensus.(*ConsensusState).defaultDecideProposal
         0     0%   100%   512.08kB  1.46%  github.com/tendermint/tendermint/consensus.(*ConsensusState).enterNewRound
```

100 subscriptions produce 32MB.

Again, no additional goroutines are running after the end of the test
(wsConnection readRoutine and writeRoutine both finishes). **It means
that some exiting goroutine or object is holding a reference to the
*Query objects, which are leaking.**

One of them is pubsub#loop. It's using state.queries to map queries to
clients and state.clients to map clients to queries.

Before this commit, we're not thoroughly cleaning state.queries, which
was the reason for memory leakage.

Refs #951

Jae: I don't know a good way to catch these errors in general, but
forcing pubsub's internal channel to have a capacity of 0 will reveal
bugs sooner, if the subscriber also has a 0 or small capacity ch to pull
from.

to better handle zero cache size

* updateToState exits early if the state isn't new, which happens after
* fast syncing. This results in not sending a NewRoundStep message. The mempool
* reactor depends on PeerState, which is updated by NewRoundStep
* messages. If the peer never sends a NewRoundStep, the mempool reactor
* will think they're behind, and never forward transactions. Note this
* only happens when `create_empty_blocks = false`, because otherwise
* peers will move through the consensus state and send a NewRoundStep
* for a new step soon anyways. Simple fix is just to send the
* NewRoundStep message during updateToState even if exit early

update README

docs/spec: some organizational cleanup

add xla as codeowner

* all: gofmt

Run 'gofmt -w .' from project root.

* Update changelog to say that I ran gofmt

* Revert "Update changelog to say that I ran gofmt"

This reverts commit 956f133ff0.

Add algorithm for Blockchain Reactor

* circleci 2.0

typo fix

Refs #1736

Bump abci version

Xla/update develop v0120

Release/v0.12.0

* Remove error from priv.PubKey()

* Update changelog

* Switch ports 466xx to be 266xx
This is done so the default ports aren't in the linux kernel's default ephemeral port range.

* Update ABCI import

* Bump cache on circleci

* Get more verbose output for debugging

* Bump abci dependency

* Fix accidental change of a block header's hash

* pin abci release

* `unsafe_reset_all` also resets addrbook.json

When executing `unsafe_reset_all` it also clear all IP addresses from
addrbook.json. This is the expected behaviour of `unsafe_reset_all`.

* Fix tests

* improve logging statements

* use correct file