Template tweaks

OK, in this pull request I've:

* Moved to using proper fanstatic for resources
* Simplified the CSS (as `release-v2.0` on core has better generic CSS for some things)
* Removed the homepage alert message as it's broken (you can only add a dataset when you are logged in... and therefore the alert message was appearing in incorrect contexts)
* Fixed up the `{% ckan_extends %}` on the templates to remove the warnings