Add's another cache that has out-preformed the MultiTriggerCache and Summing cache in benchmarks
Swap the default for the async cache to the YAC
Made def abstract
add missing needed Algebird upgrade that fixes some sparse monoid action. Also simplified the yet another cache to have less synchronization concerns
Rename new cache over to a more sensible descriptive name
Review comments
Merge branch 'develop' of github.com:twitter/summingbird into YetAnotherCache

Conflicts:
	project/Build.scala
Realise lazy stores on init
Add some option documentation
Incorporate Ian's comments
Fix typo in naming
Update year
Keep the current caches the default
Merge branch 'develop' of github.com:twitter/summingbird into YetAnotherCache
Merge pull request #470 from twitter/YetAnotherCache

Add BackgroundCompactionCache
Merge pull request #491 from twitter/jco/option_docs

Add some option documentation
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