Fix parsing for certain chords

[Quantalabs]

Should solve most of #1. It still fails for maj13/9, m6/9, and 13/9 chords. I'm not quite sure what a 13/9 chord should be.

I'm going to continue working on a couple things, however, on my fixes branch:

• Some chord parsing errors from Alternate Parsing Strategies teoria#132
• Fix 6/9 chord parsing
  • Doesn't work for any 6/9 chord prefixed with a chord type (eg. Maj6/9, m6/9).
• Default to a Major 7th instead of minor 7th for chord parsing.

[saebekassebil]

Hello @Quantalabs - Thank you for interest in Teoria! As discussed in #132 I don't agree with this way of parsing chords by default. Could you provide some example of what you are trying to achieve?

If you have some good examples and a thorough method description I would love to pull this into the main library behind a different parsing algorithm. But please don't use too much of your time trying to "fix" the parsing - as I believe it's already working as it should.

[Quantalabs]

I agree with your perspective- I've outlined a potential solution: saebekassebil/teoria#132 (comment), and I'll close this for now since it's not going to be used.