* validate reactor messages
Refs #2683
* validate blockchain messages
Refs #2683
* validate evidence messages
Refs #2683
* todo
* check ProposalPOL and signature sizes
* add a changelog entry
* check addr is valid when we add it to the addrbook
* validate incoming netAddr (not just nil check!)
* fixes after Bucky's review
* check timestamps
* beef up block#ValidateBasic
* move some checks into bcBlockResponseMessage
* update Gopkg.lock
Fix
```
grouped write of manifest, lock and vendor: failed to export github.com/tendermint/go-amino: fatal: failed to unpack tree object 6dcc6ddc143e116455c94b25c1004c99e0d0ca12
```
by running `dep ensure -update`
* bump year since now we check it
* generate test/p2p/data on the fly using tendermint testnet
* allow sync chains older than 1 year
* use full path when creating a testnet
* move testnet gen to test/docker/Dockerfile
* relax LastCommitRound check
Refs #2737
* fix conflicts after merge
* add small comment
* some ValidateBasic updates
* fixes
* AppHash length is not fixed
* 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
Updates https://github.com/tendermint/tendermint/issues/693
* Adjusted Heartbeat.Copy to return nil on
trying to copy a nil value instead of panicking.
* Also documented that WriteSignBytes panics
if the Heartbeat is nil.
