changes to make roaring bitmaps work with druid
more changes to work with druid
ntegerSet and WrappedBitSetBitmap

Adeed IntegerSet
  * IntegerSet implements Set<Integer> and wraps any one of the MutableBitmap types
  * Updated the bitmap types to include a get(int) function to return if that bit is set

Added WrappedBitSetBitmap and WrappedImmutableBitSetBitMap
  * Wraps java.util.BitSet with ImmutableBitmap and MutableBitmap interfaces
make roaring work with druid
File reformat. No code change
Changes for pull comments:

* Added MutableBitmapFactory for simple creation of mutables.
* Added capacity for WrappedBitSetBitmap and WrappedImmutableBitSetBitmap to take ByteBuffer as constructor arguments
Removed retainAll functionality
Removed authorship in comment
Merge pull request #9 from metamx/intset

IntegerSet and WrappedBitSetBitmap
Merge pull request #8 from metamx/fixup

A set changes to make roaring bitmaps work with Druid