Improvement for entering music via MIDI keyboard.

[Richard Shann]

I've been doing a bit more composing, and I realized there was an
obvious improvement to be made in switching from trying a phrase out on
the MIDI keyboard and actually entering the notes. Too often I would
find myself entering notes when I only meant to try out a phrase.
The answer is to set the button on the MIDI-in controls to "Listening
to Pitches" and leave it like that. When you actually want to enter
some pitches you can now just press the Shift key with one hand and
play in the notes with the other, releasing the Shift key at the end.

Until now, pressing the Shift key while already in Listening did
nothing. The same trick applies for the "Checking Pitches" mode.

I've added a note about this to the manual:

"For composing one method is to set the MIDI-in control panel button to
“Listening to Pitches” for trying out the melodic line you are
tinkering with, and then pressing the Shift key to actually enter the
pitches, releasing after so that further playing will be listening-
only. This is good also for transcribing by ear from a audio track -
you can listen to a phrase, reproduce it on your keyboard, enter the
rhythms from the numeric keypad and then pessing Shift enter the
pitches from the MIDI keyboard. "

This is in the source repository now and will be built overnight.

Richard