Previously, we merged CRDTs in the vnode on a CRDT Operation PUT only. This means CRDT siblings can be generated by repl, AAE, and Read Repair. CRDT values can't be dotted: There is no single PUT to overwrite previous values, instead a merge of values generates  a new value. In DVVSets they have the "anonymous list" for these generated values. In Riak it makes sense to have them undotted, as undotted siblings always survive. However, if CRDTs are undotted, then they can "explode" via Repl. To avoid this, we merge crdts in riak_object merge. It has other advantages too (mainly that yokozuna can index CRDTs). It is also a slight optimization on the CRDT path. The main thing is that this PR has DVV _and_ riak CRDT merging in riak_object merge.