Remove "Automatically set speaker count for the ivideo AC3 decoder" option.

The decoder hasn't been updated for years.
About dialog: Add back the FFmpeg compiler in the clipboard output.
DVB: Try to convert language code even if LCID was not found.
Updated German translation.
Updated French translation.
Updated Polish translation.
Disable external subtitles in capture mode.
player.html: remove width completely.

It's handled in JS.
Initialize variables in the constructor.
Enable per-monitor DPI-aware on Windows 8.1.

Fixes #3356.
Add a Doxyfile to generate source doc.

WIP
Use DEBUG_NEW instead of new.
temp