Change 2i to use long values

The original implementation of 2i used int for _int indexes
which is caused an upper bound of 2^31. The client will
now use long values eliminating this restriction.

When possible backwards compatability was maintained, specifically
regarding the @RiakIndex notation and the FetchIndex class. Users of
the IRiakObject interface calling getIntIndex() or allIntIndexes()
will need to change the type being returned from Set<Integer> to Set<Long>

This addresses #112
Modify method names to preserve backward compat

Rather than changing the return types of the existing methods
added new mthods and depricated the old ones per our discussion.
Fixed comments / @Depricated tag
Merge pull request #189 from basho/gh112-index-is-int

Change 2i to use long values