Add an option to prevent creating the external style file when saving a subtitle.
Updated LAV Filters to 0.61.2-40-42f583f (custom build based on 0.61.2-35-6c73517)

Important change:
 - LAV Video: Fix some issues with DVD subtitles (flashing, overlapping and generally all kind of timing issues) (fixes #4032).
Cosmetic changes.

* use `nullptr` instead of `0` when it makes sense
* follow the same scheme when declaring variables
Re-indent file.
Remove unused code (`MakeAACInitData`).
EVR renderers: Try to fix a deadlock.
Don't force any background color for the Shockwave graph.

This commit fixes #1747.
ISR: Render text subtitles relative to the video frame when in doubt.
Why "C:\tmp.srt"?
WebUI: Inform the web interface that no audio stream is available.
WebUI: Make use of new [hasaudio] info.
What the hell was intended here?!

Trying to make some sense of that code. Without much luck so far...
Fix: x86 and x64 versions conflicted over file associations.

4f465cf8b81f1da800b1bfc57cc48e317d24fbb5 was incomplete for Vista+.

This commit fixes #4064.
Auto mode for relative to.
Cosmetics: Use better IDs from the resource strings.