Merge pull request #14 from leftaroundabout/master

Some bug fixes and improvements.
Tiny refactoring.
Added 'verb' command, with signature @LaTeXC l => Text -> l@. Changed 'verbatim' to this signature as well (since these commands are specifically for all kinds of /plain text/ and don't require any escaping, the previous @LaTeXC l => l -> l@ didn't really make sense). Documented both functions.