Payasan

I've added linebreaking to ABC output so that it only prints four bars per line.

It's an intention I have for Payasan that the score output should be good enough for "feedback" whilst using the system, but real scores are expected to be hand edited after generation. Fixing line length to four bars rather than making it configurable seems in tune with this.

My previous designs for score languages have always suffered from having too many configuration options.