F12 / end game should stop music and channels playback

[fdelapena]

This is easy to reproduce when a game does not use music in the title scene, it will keep existing music and channels playing. In RPG_RT it will "play" silence.
This shouldn't be handled from the title scene because 2k3 1.11 can skip it, this should be handled in the end game.
Test with a 2k3 1.11 game skipping title scene and returning to a map without music: https://easyrpg.org/play/?game=itwr

[carstene1ns]

The music issue only applies to games which skip the title scene.
If the title scene is enabled, it will stop the music if it is empty. (Long) sound effects continue to play.

Stopping the audio playback could be done where the reset_flag gets cleared here to not touch the title scene, but as it will be used nonetheless, doing it there makes more sense.