Notation for chords, rolls and ornaments

[Michael-F-Ellis]

I propose to implement the following.

(abc)- d |  Chord: Sounds abc simultaneously, sustain for 1 beat
(:abc)- d | Roll: Sounds abc over 1/2 beat, sustain all tones for the remainder
(~abc)- d | Ornament: Play abc sequentially in 1/2 beat, sustaining the c for the remainder.

• The notes contained in ()'s represent one sub-beat in the same way as bare note, rest or hold and may be sustained by subsequent holds in the same way.
• Holds and rests are not allowed inside ()'s
• ()'s may not be nested.
• Octaves work as if the notes were sequential without ()'s, e.g. c (/d^adf) g produces the same pitches as c /d^adf g .

[Michael-F-Ellis]

The Ornament notation is not strictly necessary since any ornament can be written out sequentially , but given the need for Chords and Rolls it's not much more work to implement and

(~cbcbcbab)c - |
certainly seems preferable to

cbcbcbabc------- - |

[Michael-F-Ellis]

Now implemented and passing tests.