Fix: Possible double free when resetting PGS subtitles.

This resulted in random crashes when seeking quickly in a file with PGS subtitles and other various cases.

Fixes #4240.
Update translations from Transifex:

 - Catalan
 - Croatian
 - Japanese
 - Slovenian
 - Spanish

Fixes #4268.
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.
Update MediaInfoLib to v0.7.69.