ENG-4278: Prep work.  Flip polarity of single-partition check, move it
above real code to remove an indentation level.
ENG-4278: Consolidate some end-of-transaction actions at the SPIs.
ENG-4278: Add R/O state to fragment task logging
ENG-4278: For read-only final fragment tasks:
1) Clear out SpScheduler outstanding txn state early so we won't
   generate CompleteTransactionTasks
2) Early complete and flush the MP transaction when done with a
   FragmentTask when appropriate.
Remove the deployment path argument from the Schemachange client.
Now send all catalog updates with a null deployment, keeping the initial one.
Makes this compatible with VEM (somewhat) and REST (mostly).
ENG-4515: Fix broken test and take some pmartel feedback.
Merge remote-tracking branch 'origin/master' into eng4278
Merge pull request #436 from VoltDB/eng4278

Eng4278
r=rbetts
Merge remote-tracking branch 'origin/master' into ENG-4515-newjson
Merge pull request #435 from VoltDB/ENG-4515-newjson

Eng 4515 Replace JSON parser with faster/threadsafe lib.
Merge remote-tracking branch 'origin/master' into threaded-ipc
Fix whitespace.