feature request: tracker mode/view

[runlow]

Everything working the same way as now but now with an extra optional alternate text grid view in which the exact same note data is represented through numbers as if on a spreadsheet. On the horizontal axis it's channels, on the vertical axis it's time. The entries correspond to all editable attributes of notes that are currently achievable via clicking or recording.

Motivation - an alternative angle, a different insight into the music. More convenient for some types of editing. Less for others.

I don't really know so apologies but I'm guessing that it should be relatively easier to implement than the piano roll as it's basically an editable debug dump. Could be a semi-hidden for-now-just-for-debug-and-testing feature if it's too intrusive.

Great program by the way, I use it a lot.