Initial implementation of a message hub with priorities.
Merge branch 'next' into daniel_message_scheduler
Make set_priority / get_priority available on coroutines.
`with_priority_t`
Reset priority of new coroutines
Deliver local message hub messages more frequently.
Overhauled message hub wakeup a little.
Comments
Removed unnecessary include
Diverse small fixes and improvements.
Merge branch 'daniel_message_scheduler' into next