Update .gitignore.
Add support for NullVoice.
Support single-word text markups.

(No curly brackets, that is.)
Change scope name for single-word markup scopes.

Signed-off-by: yrammos <yannis.rammos@me.com>
Support changes in LilyPond 2.18.0.

Signed-off-by: yrammos <yannis.rammos@me.com>