Move after playback commands to options.

- Add an option to close and restore logo.

Fixes #325
Refactor after playback events handling.

- Playback loop now have precedence over selected action.
Add after playback command to turn off the monitor.

Fixes #1287
Support cover art for audio files.

- Don't hide logo in audio mode.
- Preserve logo aspect ratio
- Try to find cover art file in current directory
- Don't try to auto-fit in audio mode
- Allow to go fullscreen in audio mode
- Don't limit logo size

Fixes #1531
MainFrameControls: Allow auto-hiding panels in audio mode and don't
enforce toolbars.

Now that we have logo always visible it is not critical to show
toolbars.
Change keybinding for Play/Pause to Left-Up.

Fixes ticket #4440
Use internal filters by default for supported formats
Support http urls inside .ram files
Reduce variable scope when possible

Remove unused variables

Spotted by cppcheck
Fix possible null pointer dereference.

Fixes CID 966176