Use vobsubs forced subs option

As requested in: http://forum.videolan.org/viewtopic.php?p=181749#p181749

When using Vobsub subtitles there is a option to show only forced subtitles. This option is adjusted by changing single line in .idx file.

# ON: displays only forced subtitles, OFF: shows everything
forced subs: ON

Currently VLC doesn't follow this directive but instead it always shows all subtitles. Sample subtitle that shows the issue can be downloaded from: http://www.mediafire.com/?sharekey=e729bfae8e9cc77ed8f14848abf485dde04e75f6e8ebb871

We might be able to support this. It's of limited use of course, since most people will never even find that "forced subs" option. Perhaps it's better to add an option to the Subtitles menus of Qt and MacOSX, that sets wether ALL, or only forced subs should be rendered.

Should be a good 1.1 feature, easy to implement.

changed milestone to %1.1 feature freeze

Closely related to #1135

Link to the file is dead...

changed milestone to %2.0 feature freeze

Let's merge that with #1135

added Status::duplicate label

closed