check if it is getting rendered as an image rather than mathml

The problem seems to be that the content of an ensuremath environment was not getting translated (so it was rendered as an image). I modified tree_cleaner.py and that seems to have done the job.

However, on page 3, the formula at the bottom of the page has a leading }} for some reason.

\o wasn't working either, apparently because the renewcommand did not succeed in changing the behavior of \o

I am working around this problem by using \odds instead.