ucs.sty raw support

[dginev]

We received a report that --includestyles interpretation over ucs.sty leads to an infite loop. It looks like a small and focused target to improve the raw interpretation of latexml, so adding a new issue.

A minimal latex document reproduces under latexml --includestyles test.tex:

\documentclass{article}
\usepackage{ucs} 
\begin{document}
test
\end{document}