Update copyright/license.
Pull mutex utils into a separate module.
Fix missing parens; add threading-extras module.
Fix; db handle needs to be global, not thread specific, otherwise it
breaks in the pauser, and is incorrect regardless.
Catch all exceptions so that query count can be updated.
Fix incorrect useage of mutex-update!. Throw error on already
paused/unpaused. Use broadcast instead of signal, all threads need to
be notified.
Check that pause and resume can run without errors.
Working threading test, start of thread terminating test.