Address review comments
Review comments
Merge branch 'refs/heads/feature/branchF' into feature/ackOnEntry

Conflicts:
	summingbird-storm/src/main/scala/com/twitter/summingbird/storm/Constants.scala
Rename the default const to be more inline with others
Added comments
Use some good observations from comments to simplify
Review comments
use breakout
Merge pull request #396 from twitter/feature/branchF

Pluggable caches in FinalFlatMap
Merge branch 'develop' of github.com:twitter/summingbird into feature/ackOnEntry