JSAI: Q-bomb

New ship script event: shipWasDumped (opposite of shipWasScooped)
JSAI: Constrictor
JSAI: cleanup

Rename a couple of inconsistent methods
Make the AILib object use private and prototype functions for efficiency
Start reorganising the AILib file to make it easier to edit in future
Finish reorganisation of priority AI file

Also fix bug in Q-mine fleeing, make sure 'ship' property is read-only.
Fix bugs with thargoid AIs