The 2018ificiation

I think this removes most references to "hobart", "pycon", and "2017"

There are still some references to some images that we don't have a
replacement for.

Enable multi-level site-tree

* Remove the outdated compiled javascript once again
* Update the sitetree_header template to use more detail.

The extra detail here is taken from the menu_bootstrap3.html template
distributed with django-sitetree

move templates out of vendor specific locations

Lets not kid ourselves. The whole apps templates are client specific.
Lets just remove that and not think it isn't.