subtitle demux: use qsort instead of bubblesort
subtitle demux: use qsort instead of bubblesort

Most likely no major speed difference with low amount of subtitles.

xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc