Add a few lines of how to initialize a ScorePlayerMorph 
so one can write some music:

"
You can also write your own midi scores:
To try this out, execute...

	| n score | n _ 3.'number of tracks'
	score _ (MIDIScore new tracks: ((1 to: n) collect: [:i | Array new]);
		trackInfo: ((1 to: n) collect: [:i | 'Instrument' , i printString]);
		tempoMap: nil; ticksPerQuarterNote: 96).
	ScorePlayerMorph openOn: score title: 'My score'

Then open a pianoRoll and, from that, open a keyboard.  The rule is that
the keyboard will append after the current selection.  If the current
selection is muted or nil, then input will go to the end of the first
non-muted track.
"


Karl