Re: \class grob property

[Paul Morris]

Huh, looks like I already created a changes entry and regtests for this 
output-attributes feature.

https://codereview.appspot.com/308430043

https://sourceforge.net/p/testlilyissues/issues/4974/

I think I didn't do user documentation because the previous ID-only 
functionality didn't have any.  So I can work on adding that somewhere.

Looks like the infrastructure for really testing svg output is an open 
issue:

https://sourceforge.net/p/testlilyissues/issues/5185/

(And since this functionality is not visible in the svg (by itself), 
tests would need to check the svg source code rather than its visual 
result.)

Cheers,
-Paul