TOC should be visible on item click

[ghost]

When clicking on an item in TOC it disappears due to page switch.

Would give a better user experience if it was displayed until I click outside of it.

[nevir]

I think the right approach here is to AJAX in the next page (saving state across pages is less reliable)

[sjorek]

… either ajax (I like that!), or add an hash-mark to the URL (cheap) or if you're going to incorporate cookies anyway, because an upcoming pull-request from this branch https://github.com/sjorek/groc/tree/feature-collapsible-columns needs it to retain it's state over a longer period, use a (cheap) cookie …