latex.lang: only one comment context

Rename verbatim-comment to comment-env, because it is not a verbatim,
and include it in the comment context.
latex.lang: special-char context with new accents regex
latex.lang: better command regex

Some commands end with *, like \chapter*{}.
latex.lang: remove unused styles
Fix LaTeX math mode with oblivion style

In oblivion, plum3 is hard to see.
Map the math mode to a string, by default.

The math mode is now clearly visible with the 5 style schemes.

https://bugzilla.gnome.org/show_bug.cgi?id=691749
latex.lang: align the 'map-to's
latex.lang: usepackage context

Style for the package name.
latex.lang: group verbatim contexts
latex.lang: reorder contexts
latex.lang: group math contexts
latex.lang: more specific commands contexts

Apply the 'name' style to some specific commands.
Rename the 'command' context to 'generic-command'.
latex.lang: remove in-inline-math context

Use the in-math context, which is the same.