Add BPM metadata tag
Hi, I love this project, it has become my main desktop music manager now.
But I miss the a BPM column reflecting the BPM tag of the audio files, it would be amazing to have it.
I will try to build the project from source and try to work it out, although I'm mainly java developer (my pet project is also an audio player http://github.com/octaviospain/musicott)
Any hints on where to start, coding guidelines will be appreciated.