Refactor after playback events handling.

- Playback loop now have precedence over selected action.
Add an advanced option to set minimum duration for remember position
feature and allow to disable it for audio files.

Fixes #353, #3393
Refs #2179
MainFrm: Show drive label in title bar when playing DVD from root
directory.

Fixes #2194
Use c++11 random number generators.

In our case it doesn't matter that much, but why not?