Updated Stats supplier
Add more constructors
Add more metrics
Add more store stat reporters
Merge branch 'develop' of github.com:twitter/summingbird into feature/stat_store

Conflicts:
	project/Build.scala
Use map rather than mapValues to avoid unknown lazy behavior
Remove other usages of mapValues from the store stat reporters
Merge branch 'develop' of github.com:twitter/summingbird into feature/stat_store

Conflicts:
	summingbird-online/src/main/scala/com/twitter/summingbird/online/executor/Summer.scala
Merge pull request #495 from twitter/feature/stat_store

Feature/stat store