Merge pull request #12 from singhala/develop

 implement toString, equals, hashCode and fix test resource check in VersionedKeyValSource
add mappable.
Fix resourceexists bug.
Merge pull request #14 from twitter/feature/mappable

VersionedKeyValSource extends Mappable[(K,V)]
upgrade to bijection.
Merge pull request #15 from twitter/feature/bijection

Upgrade to use new Bijection library
release v.
Merge branch 'release/0.1.0' into develop
bump to snap.
add in error handling lzo codec, bump scalding to 0.8.2