* Fix random distribution in bitArray.PickRandom

Previously it was very biased. 63 "_" followed by a single "x" had
much greater odds of being chosen. Additionally, the last element was
skewed. This fixes that by first preproccessing the set of all true
indices, and then randomly selecting a single element from there.

This commit also makes the code here significantly simpler, and
improves test cases.

* unlock mtx right after we select true indices

* first draft for ADR summarizing discussion from:
https://github.com/tendermint/tendermint/issues/1622

* fix link and add comment about pub-key per message and fix link

* fix link and add comment about pub-key per message; also:
 - fix link
 - add little diagram
 - fix typo

* Add a slightly different approach

* typo and ADR number

Bucky/adr 029

There's a time window after we call RotateFile() where autofile#index+1
does not exist. It will be created during the next call to Write(). BUT
if somebody calls NewReader() before Write(), it will fail with "open
  /tmp/wal#index+1/wal: no such file or directory"

We must create file (either by calling gr.Head.openFile() or directly)
during NewReader() to ensure read calls succeed.

Closes #2538

* docs: fix links

* docs: add readme from each section to the sidebar

* Disable transitioning to new round upon 2/3+ of Precommit nils

Pull in ensureVote test function from https://github.com/tendermint/tendermint/pull/2132

* Add several ensureX test methods to wrap channel read with timeout

* Revert panic in tests

also, fix potential bug in Or function

Also make reversing a slice more efficient

* timeouts as time.Duration are also breaking for old configs
* split BaseConfig#ValidateBasic into smaller methods

* docs: links to dirs need a slash

* docs/spec/abci: consensus params and general merkle

* remove some XXX

* config: remove Mempool.RecheckEmpty

* docs: remove recheck_empty

This change doubles the speed of the mempool's reaping.
Before:

BenchmarkReap-8   	    5000	    365390 ns/op	  122887 B/op

After:

BenchmarkReap-8   	   10000	    158274 ns/op	  122882 B/op

* minor doc cleanup

* docs/tools: link fixes and readme

* docs/networks: networks/local/README.md

* docs: update vuepress config

* docs: fixes from review

* tmlibs -> libs

* update changelog

* address some comments from review of #2298

* first commit

finalize rebase

add protoc_merkle to Makefile

* in progress

* fix kvstore

* fix tests

* remove iavl dependency

* fix tx_test

* fix test_abci_cli

fix test_apps

* fix test_apps

* fix test_cover

* rm rebase residue

* address comment in progress

* finalize rebase

* switch to amino for SignBytes and add Reply with error message

- currently only Vote is done

* switch Reply type in socket for other messages

 - add error description on error

* add TODOs regarding error handling

* address comments from peer review session (thx @xla)

 - contains all changes besides the test-coverage / error'ing branches

* increase test coverage:

 - add tests for each newly introduced error'ing code path

* return error if received wrong response

* add test for wrong response branches (ErrUnexpectedResponse)

* update CHANGELOG_PENDING and related documentation (spec)

* fix typo: s/CanonicallockID/CanonicalBlockID

* fixes from review

* Implement issues 2386: add synchronization in lite verify and change all Certify to Verify

* Replace make(chan struct{}, 0) with make(chan struct{})

* Parameterize memroy cache size and add concurrent test

* Refactor import order

docs: Add version

* add missing options to config.toml template and docs
Refs #2232
* config#ValidateBasic
Refs #2232
* [config] timeouts as time.Duration, not ints
Why:
- native type provides better guarantees than ", in ms" comment (harder
to shoot yourself in the leg)
- flexibility: you can change units

* fix Group.RotateFile need call Flush() before rename. #2428
* fix some review issue. #2428
 refactor Group's config: replace  setting member with initial option
* fix a handwriting mistake
* fix a time window error between rename and write.
* fix a syntax mistake.
* change option name Get_ to With_
* fix review issue
* fix review issue

* Add additional metrics to p2p and consensus
Partially addresses https://github.com/cosmos/cosmos-sdk/issues/2169.
* WIP
* Updates from code review
* Updates from code review
* Add instrumentation namespace to configuration
* Fix test failure
* Updates from code review
* Add quotes
* Add atomic load
* Use storeint64
* Use addInt64 in writePacketMsgTo

* handle SIGHUP explicitly inside autofile
Refs #2260
* libs: Use consistent channel suffix

* stop node upon receiving SIGTERM or CTRL-Ceven during genesis sleep by setting up interrupt before starting a node

Closes #2434

* call Start, not OnStart when starting a component to avoid:

```
E[09-24|10:13:15.805] Not stopping PubSub -- have not been started yet module=pubsub impl=PubSub
```

being printed on exit

version: types

Master back to develop

Release/v0.25.0

* docs: link consensus to blockchain spec. closes #2422

* docs: deprecate research section. closes #2401

* docs: fix some links

* docs: fix some markdown lists

* docs: fix more links

Merge master to develop

Release/v0.25.0

* mempool: update some comments

* make build_c

* docs: notes about databases and WAL files

* docs: determinism. closes #1279

* docs: small note about query paths. closes #2090

* docs: gas

* docs: abci consensus params

This also refactors the prior mempool to filter to be known as
"precheck filter" and this new filter is called "postcheck filter"

This PR also fixes a bug where the precheck filter previously didn't
account for the amino overhead, which could a maliciously sized tx to
halt blocks from getting any txs in them.

* Move maxGas outside of function definition to avoid race condition
* Type filter funcs and make public
* Use helper method for post check
* Remove superfluous Filter suffix
* Move default pre/post checks into package
* Fix broken references
* Fix typos
* Expand on examples for checks