Styles
Styles are used to categorise Midi Tracks by analysing the notes played in the track.
If a track is empty, it is assigned a Style of NoStyle.
If all the notes are on midi channel 10, it is assigned a Style of Percussion.
If the track is nearly empty, it is assigned a Style of Sparse.
If the track contains mainly block of chords, it assigned a Style of BChords.
If the track contains mainly bass notes, it assigned a Style of Bass.
If the track contains nearly all chord notes (by comparing it with the ChordFile), it is assigned a Style of AChords.
Otherwise, it is assigned a Style of Melody.