* Move evSubscrip from dbEvent.[ch] (private) to dbChannel.h (public).
* Split up db_post_single_event_private into two parts:
..._first creates a new db_field_log chunk and copies from db.
..._final puts a db_field_log into the event queue.
* Add a typedef for the pre-event-queue recursive callbacks.
* Add a register function for the callback (plus void* arg) to filter and
plugin interfaces.
* Add the code that builds up the pre-event-queue callback chain.
* Changes to the test files to compile (no tests added yet).
* Fix missing include in db_field_log.h.
4dd42383ef