Change notemap to concert pitch and add --transpose CLI flag

[petermoz]

This implements half of #19, also discussed here: cardonabits/haxo-hw#60

This PR changes the notemap to be in concert pitch: after this change you can think of the notemap as translating between "keys pressed" and "note written on the music". This is constant across all saxophones - i.e. the lowest note in the notemap will represent "Low Bb" (ignoring Bari Low A).

Since the notemap will be concert pitch, we also introduce a CLI flag to change the transposition (i.e. the mapping from "written note" to "how the note sounds"), which is different for all saxophones. This --transpose flag can be set on the command line or in the haxo.service settings and defaults to -14 to match the current haxophone default behavior (a tenor saxophone).

Here's the --transpose setting you should use to achieve different instruments

instrument	--transpose
soprano	-2
alto	-9
tenor	-14
bari	-21

[petermoz]

@gerdb - I saw in #18 that you wrote a notemap viewer. In this PR (and related discussions) we've proposed to redefine the notemap to be in concert pitch. I assume that'll necessitate changes to your viewer to match.

I've found the viewer very handy by the way, I keep forgetting how to play everything above high D :)

[jcard0na]

In this PR (and related discussions) we've proposed to redefine the notemap to be in concert pitch. I assume that'll necessitate changes to your viewer to match.

Well spotted. My fingering viewer also broke with this change (https://haxo-notemap.nn.r.appspot.com/). I just fixed it.

(But I prefer @gerdb's viewer!)

[gerdb]

Updated the viewer to concert pitch.