Working on getting a better model for Sources.
Added a check to CachingBlobStore and CachingObjectStore to see if an
object is in the cache before putting.
Merge branch 'master' into SourceWork
Changed Sources to not implement iterable and to return closeable
iterators. Also fixed some broken copyright messages.
Added a constructor to ThreadedMapper so that threads are named
appropriately.
Miscellaneous new functions
Incremented snapshot version number.