deccc608: fix rollup style CC problems

The timing of the "erase display" command was incorrect for rollup CC
and erased subtitles immediately after they were displayed.

When rendering, sometimes rollup subtitles arrived at the renderer far
after the frame they should be rendered on.  So push rollup subtitles
into the pipeline for each new character received when rendering.


git-svn-id: svn://svn.handbrake.fr/HandBrake/trunk@6421 b64f7644-9d1e-0410-96f1-a4d463321fa5