When backend has  capability, encode correctly (e.g. handoff)
Fix guard: we *are* in riak_object.erl
Fix guard: review style
Symmetry: #r_object{} handling in from_binary/3
Bugfix: use correct args for riak_core_apl:get_primary_apl()
Merge branch 'slf-r_object-handoff-encoding-fix'