Fix positioned events' y-position when pan-and-scan is used.
Fix positioned events' y-position when pan-and-scan is used.

git-svn-id: 947b4ff483bb4cc5004120385d99e48ac0944466@28823 b3059339-0415-0410-9bf9-f77b7e298cf2

stps/libass,Distrotech/libass,Akemi/libass,Akemi/libass,torque/libass,mwgoldsmith/libass,tgoyne/libass,grigorig/libass,pigoz/libass-ct,sanyaade-g2g-repos/libass,vault/libass,sanyaade-g2g-repos/libass,torque/libass,richardpl/libass,blinkseb/libass,richardpl/libass,MrSmile/libass,libass/libass,MrSmile/libass,ShiftMediaProject/libass,blinkseb/libass,Distrotech/libass,pigoz/libass-ct,tgoyne/libass,tgoyne/libass,rhlee/libass,astiob/libass,richardpl/libass,asimonov-im/libass,mwgoldsmith/libass,vault/libass,ShiftMediaProject/libass,Akemi/libass,grigorig/libass,asimonov-im/libass,Distrotech/libass,rhlee/libass,sanyaade-g2g-repos/libass,torque/libass,libass/libass,stps/libass,xbmc/libass,astiob/libass,xbmc/libass,rhlee/libass,pigoz/libass-ct,stps/libass,blinkseb/libass,mwgoldsmith/libass