Fix support for todonotes

[mukobi]

Have you got it working with the todonotes package? Seems to not show \todo{}s

Repro:

% in the header
\usepackage{todonotes}

...

% in the body
\todo{Foobar}

Observed - expected: The todo doesn't show up, unlike in normal LaTeX papers.

Note I get a warning to add \setlength {\marginparwidth }{2cm} before including todonotes, but that doesn't seem to fix it.