Updated LAV Filters to 0.62-36-126eb21 (custom build based on 0.62-31-45b14b6).

Important changes:
 - LAV Audio: AAC seeking improvements
 - LAV Splitter: improved GIF support (including animated GIF).
 - Updated ffmpeg library.
Sync Renderer: Fix the computation of the FPS used by the ISR.

We need to use the average FPS not the currently measured FPS.

Not doing that could lead to wrong timings for subtitles using frame-based timings.

Fixes #4857.
Cosmetic: Fix a typo.
QuickTime graph: Ensure all errors are correctly reported.

Ref: #4863.
Update translations from Transifex:

 - Arabic
 - Basque
 - British English
 - Chinese (Simplified)
 - Catalan
 - Croatian
 - Czech
 - Dutch
 - French
 - Galician
 - German
 - Hungarian
 - Italian
 - Japanese
 - Polish
 - Portuguese (Brazil)
 - Slovak
 - Spanish
 - Swedish
 - Thai
 - Ukrainian
 - Vietnamese
Playback option page: Minor UI adjustment.

Ref: #4766.
Formats option page: Reworked UI.

Replace the text buttons by icon buttons and add a new button to clear all associations.

Also replace the "with icons" checkbox text with something clearer now that there is more space.

Fixes #4687.
Subtitles options: Clarify the "Delay interval" setting.

 - Rename it "Delay step".
 - Add a tooltip to explain what it does exactly.

Fixes #4865.