Lilypond note calculation overhaul

[Brayconn]

I've wanted drumburp's lilypond export to have support for more note types for quite a while now, and here it finally is. All the old hard-coded stuff has been replaced with an actual equation that (as far as I can tell) would work with any Counter. I've also added a bunch of new counters: Quintuplets, Septuplets, and 64th notes.

A few things to note:

• The tuplet calculator doesn't reduce its fractions at all, so the numbers it produces can get a bit ridiculous... They are all "correct" though, and reducing them is well within the realm of possibility.
• The majority of the code in makeLiliyDuration should probably be moved into the beat object to improve performance. The current code can get pretty slow for full songs... Done.
• I'm not 100% satisfied with the actual text for the new Counters. If anyone has some better ways of counting them I'd love to see them!

[Brayconn]

Quick update, it turns out I actually got part of the calculation for compoundStart wrong. Ratios are supposed to be /, so an 8th note triplet would be 3/2, a quintuplet 5/2, etc. And it turns out the code I put there isn't calculating the latter value of the ratio correctly.

Should I open a new pull request for this, or try and re-open this one?

[Whatang]

Hi - sorry not to respond, been doing other things. I think opening a new PR would be best.

[Brayconn]

Ok. I just fixed the code this evening, so I'll see about getting a new pull request made in the coming days