Add remaining bucket properties to PBC

*NOTE: This is a protocol change only, related libraries that link directly (Riak, Erlang/Python/Java clients) will break with this patch until changes have been propagated.*

This adds the remaining known bucket properties to the PBC messages.  An effort has been made to avoid reimplementing JSON; instead the messages strive to have a more compact form but the `riak_pb_codec` module modulates formats as necessary for compatibility. Additionally, arbitrary properties are not supported (although one can set them over HTTP), only properties that are known and used in Riak sub-applications are included.