Don't prevent the users from using the ISR if they choose not to block VSFilter like filters.

This commit fixes ticket #4231.
PGS subtitles: Enqueue empty segments to be sure subtitles are properly cleared when using the queue.

This is a work-around and will be improved later.

Refs: #3691.
Update translations from Transifex:

 - Croatian
 - Dutch
 - German
 - Japanese
 - Spanish
 - Ukrainian
 - Vietnamese
Update files for v1.7.5 release.
Update docs/Release.txt.
Set MPC_NIGHTLY_RELEASE to 1.
ISR: Disable "Save subtitle" command when it's unsupported.

Based on Kasper93's patch.
Cosmetic: Prefix (smart) pointers with p in SubtitleInput struct.

It's clearer that way.
Use AtlEscapeUrl/AtlUnescapeUrl to do URL encoding/decoding.

This is now available outside of ATL Server. It avoids using our incomplete URL encoding function.
PGS subtitles parser: Use CAutoPtrList to avoid manipulating raw pointers.
Docs: Change the tag numbering of LAV Filters/ffmpeg.

Follow the same principle than the nightly builds numbering now that we use `git describe`.

MPC-HC 1.7.5 was a hotfix release so neither LAV Filters or ffmpeg were updated so we won't have any tag collision.
Updated LAV Filters to 0.61.2-11-g70ec47a (custom build based on 0.61.2-6-002d1f2)

Important changes:
 - LAV Splitter: Alternate audio support for HLS (ticket #3575)
 - LAV Video: Support VP7 video
 - LAV Video: Use the MediaFondation WMV decoder on Windows 7+ instead of the DMO WMV decoder
 - Updated ffmpeg and libbluray libraries
WebUI: Inform the web interface that no audio stream is available.
WebUI: Make use of new [hasaudio] info.
Fix some CPPCheck warnings or mark them as intentional.
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.