Split/paver LMS-11211

@jzoldak @cpennington  Please review.
- *Acceptance Tests:*  For now, I've disabled testing with both Mongo and Split, by default, since there are failures that we'll need to debug.  One can still pass in "default_store"=split as an argument to test with Split.
- *BokChoy Tests:* I'm having Jenkins test the BokChoy tests since my local VM is currently screwed up.  If there are test failures specific to Split here as well, we'll disable Split for default for BokChoy as well, in this PR.  We'll open a new story or new bugs for each.
Here's the TODO item to add Split to the list of stores to test, if the caller hasn't explicitly provided a store.