Merge branch 'charability-trigger-hotfix' into 'next'

Charability trigger hotfix

Apparently when I made `P_RunTriggerSpecial` less than 3 years ago (August 2014) and cleaned up the trigger linedef code, I accidentally inverted the ability check for linedef types 305-307 by mistake, thereby causing the linedefs to activate for anyone EXCEPT those with the ability instead. Whoops.

See merge request !205