Add an interface for channel list and change to the web server.

This change adds a JSON interface for obtaining the list of channels
currently available via the DVB interface in MPC-HC, and a simple facility
which allows the client to change the currently played channel.
CAppSettings: Remove the copy constructor and assignment operator.

We don't want to accidentally copy the settings.

Also don't mark the constructor as virtual.
Don't warn the user when some DVD hooks fail.

Those hooks aren't critical for DVD playback and they often fail due to an incompatibility with NVIDIA drivers on some systems which unfortunately we can't fix on our side.

Refs: #3739.
VSFilter: Be more careful when using IMediaSample2 interface.
Sync Renderer: Remove some unneeded casts.
Update translations from Transifex:

 - Basque
 - Catalan
 - Chinese (simplified and traditional)
 - French
 - German
 - Greek
 - Hungarian
 - Japanese
 - Polish
 - Slovak
 - Turkish
 - Ukrainian
Add an option to prevent creating the external style file when saving a subtitle.
Enable external default style export even for SSA/ASS formats. ???
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).
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.