add parser / standardized abstract data format

[splendidtoad]

https://github.com/pianosnake/ireal-reader (Nice JSON struct here)
https://github.com/ironss/accompaniser/tree/master/doc

[splendidtoad]

https://github.com/rubiety/chords-json
https://github.com/rubiety/irealb_parser

[splendidtoad]

...and, bingo: https://github.com/drs251/pyRealParser