Fix vox sensor.
Fix #388: Incorrect C4 timing checks.
Fix #384 (possibly): Welding a fridge/freezer does nothing.
Fix for #383 - C4 deleting fridges full of corpses.
Fix for #382 - Bombs not deleting themselves and the fridge they're in.
Fix #384 - Fridges can be opened while welded shut.  Also discovered this extended to secure lockers.
Fix #381 - Poster duping
Changelog update.