change post_case_blocks and one test to use form locking

the rest of the tests call a post_xform_to_couch, which goes through the same code path
but releases the lock before returning
update couchforms version
Merge branch 'master' into form-locking

Conflicts:
	setup.py
Merge pull request #197 from dimagi/form-locking

change post_case_blocks and one test to use form locking