MathQuill enhancements: making simple character commands like N, C, o, denoted by simple characters instead of decorated ones (because they'll probably be used as variables in GeoGebra)

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@23909 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e