Removed Timestamp trait dependency on ScnTimestamp implementation
Moved Timestamp trait from Scn to Nrv
Fetch timestamp from ConsistencyMasterSlave instead of from Mry Database
Merge branch 'master' into manu-extract-timestamp

Conflicts:
	mry-core/src/main/scala/com/wajam/mry/storage/mysql/MysqlTransaction.scala
	mry-core/src/main/scala/com/wajam/mry/storage/mysql/TableContinuousFeeder.scala
	mry-core/src/main/scala/com/wajam/mry/storage/mysql/TableTimelineFeeder.scala
Merge pull request #51 from wajam/manu-extract-timestamp

Fetch MRY timestamp from new ConsistencyMasterSlave (READ DISCLAIMER)