HNotate

Copperbox revision 528.

Abc generation now works for the HNotate2 branch with a new simple interface. I've added the usual Bulgarian 6 example, which is described by this:

bulgarian6 :: AbcOutput
bulgarian6 = tune $  tune_number 1 
                 <$> title "Bulgarian (?) 6"
                 <$> composer "Unknown"
                 <$> key a_major 
                 <$> meter 2 4 
                 <$> current (stdInterp bars1_4)

bars1_4 is the usual note list.