Update of property assignment syntax for Lilypond conversion (issue #1791)

[jeremy9959]

The property assignment syntax for lilypond has been updated, so that instead of

\override Property #'Attribute = value

we have

\override Property.Attribute = value

This responds to issue #1791

[coveralls]

coverage: 92.998%. remained the same
when pulling ed9f50f on jeremy9959:jeremy9959-1791
into eb5a88f on cuthbertLab:master.

[jeremy9959]

The flake errors refer to "" vs '' and most have nothing to do with changes I made, so I hesitate to get involved in that.

[mscuthbert]

closing and reopening to get a clear flake sign.

[mscuthbert]

Hi -- those flake things were "caused" by you -- I'll do a quick fix.

When you modified the Rest #'Property to Rest.Property you removed the single-quote within double-quotes. Therefore there was no longer a reason why we should use double quotes. Easy fix for me as penance for letting this slip.

[mscuthbert]

thanks!

[jeremy9959]

Thank you!