SubPicAllocator: Add a thread-safe way to free the static subpicture.

This is for later use but the static subpicture was currently freed without any locking when changing the DirectX device and I am not quite sure this was safe at all.
ISR: Text subtitles were incorrectly displayed after switching from PGS/DVB subtitles.

This commit fixes #????
Add an implementation of CStdioFile that supports file bigger than 2GB.
Use CStdioFile64 to open subtitles files and remove the try/catch that used to hide the issue.
Prevent the low-merit fall-back on internal LAV Splitter to demux raw subtitle formats.

This commit fixes #3544.
Lite builds: Fix a minor inconsistency regarding the output directory.

Lite debug builds use "mpc-hc_x??_Debug Lite" while release builds always used "mpc-hc_x??" for both normal and lite builds.
Fix: x86 and x64 versions conflicted over file associations.

4f465cf8b81f1da800b1bfc57cc48e317d24fbb5 was incomplete for Vista+.

This commit fixes #4064.
Language menu: Ensure "Language" always appears in English in menu entry.

If "Language" doesn't appear in the translated string, "(Language)" will be appended automatically.