Removes hard coded links to /admin

The _editor_js.html page has been modified in order to get the urls to the
various views through the {% url %} tag and add them to the global window
variable. I believe that this is actually the best solution in our case
and I like it much better than the other available options.
Merge branch 'master' of https://github.com/spapas/wagtail into spapas-master
stylistic tweaks to b7158bb3fab5ba8923dc4311e4b538e4e21316e9 (camel case for js vars; using a dict rather than adding vars indefinitely to the window scope; avoiding potentially dynamic code inside compress blocks)