Added file opening in default program

I have updated the current snapshot build v0.1.1 with the simplest and quickest solution to platform independent audio pre-listening. Just double-click a file and it will open in your current default audio player.

I consider the ability to easily determine, what's in a file that otherwise just appears as label in a table, a very important foundation for deciding on track names and plan re-arrangements of files.

Proper integrated playback of audio files of more than the most basic audio encodings, will involve some kinds of platform specific low-level libraries. As I would like to concentrate more on file organization for sessions, at this point, I see default player usage as a good way to push dealing with those licensing terms, platform specifics and installation issues out of my way for a while.

But now I can directly go on to think about the more complex task of allowing re-arrangement of files, adding tracks, bulk rename after import, and so on, and later come back to integrating some nice lean playback solution.