Link to the root cause of throwable in our help message
Merge pull request #818 from twitter/better-stack

Link to the root cause of throwable in our help message
Noticed an inconsistent type
Merge pull request #821 from twitter/sumByKey-rettype

Noticed an inconsistent type
Make VersionedKeyValSource validate explicitly provided versions
fix comments
Merge pull request #824 from isnotinvain/alexlevenson/VersinonedKeyValSource

Make VersionedKeyValSource validate explicitly provided versions
Remove answered TODO question from VersionedKeyValSource
Merge pull request #825 from isnotinvain/alexlevenson/VersinonedKeyValSource

Remove answered TODO question from VersionedKeyValSource
corrected twitter handle for one of the contributors.
Merge pull request #828 from CruncherBigData/patch-1

corrected twitter handle for one of the contributors.
Fix RuntimeStat's backwards use of WeakHashMap
Use both weak keys and values
Merge pull request #829 from isnotinvain/alexlevenson/RuntimeStatsMemLeak

Fix RuntimeStat's backwards use of WeakHashMap
bump version to 0.9.0rc16
Merge branch 'release/0.9.0rc16'

Conflicts:
	README.md
	scalding-core/src/main/scala/com/twitter/package.scala
	version.sbt