Adding support for an opaque user_data field on Action/Trigger events:

Adding support for an opaque user_data field on Action/Trigger events:

* New column on action_trigger.event and fieldmapper field (user_data) to hold json-encoded data blob
* New optional param to event creation calls to pass said data blob
   (related, added a granularity param to targeted event creator -- pass undef in that position to ignore def granularity, as before)
* New grouped event environment array, called user_data, carrying the peer user_data fields to target and event
* New grouped event method, environment.EventProcessor.findEvent(), for grabbing a specific Event instance (fully fleshed)

git-svn-id: svn://svn.open-ils.org/ILS/trunk@15026 dcc99617-32d9-48b4-a31d-7c20da2025e4