Let ChordNameVoice use the same performers as Voice

Let ChordNameVoice use the same performers as Voice

In particular, ties should be heeded when creating Midi from a
ChordNames context as they result in the omission of the engraved
chord name if an identical chord follows.  Reasoning for beams and
slurs is fuzzier, but an articulation different from the same music in
a regular Voice context does not seem to make sense.

[lemzwerg, 2013-01-04 13:56:30]

LGTM.  Thanks for the quick fix.

[J. Rohrer, 2013-01-04 19:32:02]

Tested this, specifically to see if 

\midi { \context { \ChordNameVoice \remove Note_performer } }

still works to silence the chords from a ChordNames staff (and nothing else) in
MIDI. It does, so LGTM, if that's of any value.


[Thus I learned something about contexts today: I would not have naively
expected

  \context { \AlreadyDefinedContext \name NewContext },

to actually create a new, independent context, since the command looks more like
a tweak on \AlreadyDefinedContext. But obviously this is useful.]

[dak, 2013-01-04 19:38:20]

On 2013/01/04 19:32:02, J. Rohrer wrote:

> [Thus I learned something about contexts today: I would not have naively
> expected
> 
>   \context { \AlreadyDefinedContext \name NewContext },
> 
> to actually create a new, independent context, since the command looks more
like
> a tweak on \AlreadyDefinedContext. But obviously this is useful.]

\AlreadyDefinedContext _always_ creates a new, independent context copy.  It is
just that at the end of the context definition, whatever the name ends up to be
is telling the output definition just where to write this new context
definition.  If you don't change the \name, it is going to end up in the place
of the old definition.