Add link to TIDE project
Modify default.html to use MathJax
Add jekyll-tagging plugin and modify files to make it work

This required changing the layouts. From now on main pages
should use layout: pages. The only thing which should use
layout: default is other layouts. The default layout sets up
the navigation, sidebar and footer, but leaves a blank space
for the content in the middle.
Modify stylesheet to get tag cloud to look right
Another couple of tweaks to get the tag pages to look good
The tag cloud just looks stupid