Parse context definitions and context modifications in \notemode

Parse context definitions and context modifications in \notemode

Since context modifications and context definitions are somewhat more
concerned with musical content, it makes sense to parse them in a mode
where note names are recognized and can be used in music and scheme
function arguments.

The main argument for a separate INITIAL lexer mode is for being able
to specify REAL number values in a lenient syntax, such as .5\cm.
However, dimensions are almost never used in context definitions
or modifications but rather in output definitions like layout, midi,
paper and header blocks.


Also contains commits

convert-ly rule for simplifying \stringTuning


Run scripts/auxiliar/update-with-convert-ly.sh

[dak, 2013-09-18 21:10:11]

Rebase on current master