IntegerSet 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
It is essentially "contains" but java.util.BitSet uses it this way, so I went with convention.