Less bold in overview of referencing tags

It was a bit too much to put sections etc. in bold.
Changed text for tag view

We now display the MathJax / XyJax version by default, so the line
introducing the content was a bit off.
Centered the body of the website

I'm not really conviced by the result though.
Fixed the main regular expression

Tag 072I contained a question mark in the \section command, which wasn't
parsed.
Now the comments and comment input sections toggle

Hence they're not displayed by default, you have to toggle them. Let's
see whether this is an improvement.