TransactionQueue improvements (openethereum#5917)

* Order by id instead of hash.

* Minimal gas price bump.

* Avoid to construct oversized transaction packets.

* Fix RPC.

* Never construct oversized transactions packet.

* Never construct oversized packets.

bumped nanomsg

js-precompiled 20170608-105446

js-precompiled 20170608-105446

whitespace

Backporting to beta (openethereum#5657)

* Add CHANGELOG.md (openethereum#5513)

* Add CHANGELOG.md

* Add some more verbose CHANGELOG information for beta and stable releases

* Add dates to releases

* reorg into blocks before minimum history (openethereum#5558)

* v1.6.7

js-precompiled 20170411-114812

js-precompiled 20170328-003032

[stable] Backports (openethereum#5297)

* v1.5.12

* Fine grained snapshot chunking

[stable] Backports (openethereum#5297)

* v1.5.12

* Fine grained snapshot chunking