Frefactored the fretboardModel and chordListModel to avoid "eventing",
pushing new chords into the list and then firing events. This made sense
in the desktop app but not for the webservice, and it's a little more
clear now.
Renamed and rearranged packages. There might eventually be other kinds of
instruments supported (it looks like Harp is one of them) and these should
each get their own package
Merge pull request #30 from ConchordanceProject/fretboard-refactor

Fretboard refactor