Changes

Line 29: if ( $path && @file_exists( $path ) ) {

Check pre-reqs are good for Scribuntu.

service apache2 restart

I tried various methods to get MathML to work and always failed. It looks like the community bet on Mathoid working out, but there's been no development on it for 5 months now, and it looks dead. The good news, if that MathJax works just fine right out of the box:

Note: the last line lets you demark math with LaTeX-like syntax. I disabled it, as I use $ signs way to much in other contexts.

PDFEmbed was the extension that I never knew that I always wanted!