fontselect: minor cleanup
fontselect: minor cleanup

Use a pointer to the selected font info, instead of an index. Makes the
code a bit more readable.

xbmc/libass,torque/libass,torque/libass,Akemi/libass,stps/libass,mwgoldsmith/libass,ShiftMediaProject/libass,MrSmile/libass,grigorig/libass,Akemi/libass,sanyaade-g2g-repos/libass,stps/libass,libass/libass,torque/libass,sanyaade-g2g-repos/libass,astiob/libass,MrSmile/libass,libass/libass,Akemi/libass,xbmc/libass,sanyaade-g2g-repos/libass,astiob/libass,mwgoldsmith/libass,grigorig/libass,stps/libass,mwgoldsmith/libass,ShiftMediaProject/libass