Fixes crash on OS X if dir_watch_Poll is called during init before dir_watch_Add, refs #2427, #2650

git-svn-id: http://svn.wildfiregames.com/public/ps/trunk@15748 3db68df2-c116-0410-a063-a993310a9797
fix a rare case where a Petra attack would not know its target is already destroyed

git-svn-id: http://svn.wildfiregames.com/public/ps/trunk@15749 3db68df2-c116-0410-a063-a993310a9797
reset the trigger script when changing map, fix #2793

git-svn-id: http://svn.wildfiregames.com/public/ps/trunk@15750 3db68df2-c116-0410-a063-a993310a9797
Merge 'remotes/trunk'