Ops with builders and simple responses

All operations are now created with builders for consistency.

Operations which require more than a simple response type have
the response class as a public static nested class.

At the core we no longer cache and return query information. This
will be handled in the user API level.
Changed fetch/store response builders

These are now like the ones in the crdt ops where they
extend one another.
Forgot to get rid of RiakResponse

It's no longer used.
Merge pull request #335 from basho/finalize-core

Finalize core