Merge pull request #91 from wajam/manu-txrecorder-test-bis

Transaction recorder improvements and tests
Faster Json rendering from Lift representation
Remove FileTransactionLogItereator auto close.

Now close it everywhere explicitly except in unit tests.
Merge pull request #93 from wajam/alex-json-fast-render

Faster Json rendering from Lift representation
Merge pull request #92 from wajam/manu-txlog-truncate

Implemented transaction log truncate
Rewritten tx log read. Can now read from a specified Index or Timestamp.
Cleanup
Merge branch 'manu-txlog-read-refactoring' into manu-log-recovery

Conflicts:
	nrv-core/src/main/scala/com/wajam/nrv/consistency/persistence/FileTransactionLog.scala
	nrv-core/src/test/scala/com/wajam/nrv/consistency/TestTransactionRecorder.scala
Working and unit tested transaction log recovery