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.
WebUI: Cleanup.
WebUI: only make available to global scope the functions we need to access.
Use AtlEscapeUrl/AtlUnescapeUrl to do URL encoding/decoding.

This is now available outside of ATL Server. It avoids using our incomplete URL encoding function.
Readme.md: switch to SVG badge.
Update ZenLib to v0.4.29 r458.

Conflicts:
	docs/Changelog.txt
Update MediaInfoLib to v0.7.69.