Adds MAC for securely passing contexts through client.
Replaces form with more compact span markup.
No more JS/PHP globals.
Simplifies context pushes/pops
Merge pull request #3 from mrclay/stuff

Adds MAC for securely passing contexts through client.
User hover menu as ajax view.
Showing a throbber while loading the hover menu.
Moved js view to js/lazy_hover.