* Clear out complex get_message_instance_receive how that many-to-many works.
* Create decent error messages when correlations fail
* Move correlation checks into the MessageInstance class
* The APIError could bomb out ugly if it hit a workflow exception with not Task Spec.
b439f69f2 Merge pull request #296 from sartography/bugfix/subprocess-access-to-data-objects
6d2a2031e update spiff subworkflow tasks too
992c38671 make data objects referenceable within subprocesses
6c8ff5cdf allow subprocesses & call activities to have different data copy policies
2b14f3a48 initialize subprocesses in _update_hook instead of _on_ready_before
791f335d5 Merge pull request #295 from sartography/improvement/remove-camunda-from-base-and-misc-cleanup
28b579beb remove a few unused, duplicative, and debugging methods
8f14d1098 remove some other unused diagrams and tests
408bc6734 rely on top level camunda parser for almost all namespace references
895b2cc9b remove camunda namespace from base bpmn parser
76ecbf7cc Merge pull request #294 from sartography/bugfix/reactivate-boundary-event
82b6c8ad4 hack to ensure timers (and other events) are reset if returned to via loop reset
590903f47 Merge pull request #292 from sartography/feature/multiinstance-refactor
537490043 fix bug & typo
f31726db1 raise error on attempting to migrate workflows with MI
44e6d08d8 create spiff multiinstance task
2168c022b create camunda MI that approximates what it used to do
9894cea59 some improvements and bugfixes
f857ad5d4 remove some now unused functionality & tests, create a few more tests
6fead9d04 updated serializer & fixes for most tests
ec662ecdd add parallel multiinstance
bd19b2a8a working sequential multiinstance
2f9c192b6 further cleanup around _update_hook
947792bf6 fix bug in exclusive gateway migration
d3d87b28d add io spec to all tasks
f1586e275 add support for standard loop tasks
git-subtree-dir: SpiffWorkflow
git-subtree-split: b439f69f23b547df4de1e8e0c636997f2fd4e33b
* Link between message instance and correlations is now a link table and many-to-many relationships as recommended by SQLAlchemy
* Use the correlation keys, not the process id when accepting api messages.