init_c now asserts that deps passed are unique.
Tests now have their own init_c.
Added docblock to init_c.
Queues and dispatchers are now strongly associated with a thread.

- Dispatchers can now detect if they're dispatching on the wrong thread.
- Publishers can now detect if they're dispatching to a thread.
  This may not work correctly in the case where the actual sub is
queuing to another thread.