RTL: fix position of help icon in filter_horizontal m2m widget

--HG--
extra : rebase_source : a201efaee395d8d3bff8e88799c30830346a9e2b
Fix nginx config to work on more recent ubuntu versions.

Not sure how backwards compatible this is.
Please see: http://stackoverflow.com/questions/8768946/dealing-with-nginx-400-the-plain-http-request-was-sent-to-https-port-error
dynamically generate top margin of admin content area
contentMargin out of global namespace
Force csrf token generation on every request with cache middleware. Closes #676.
Use a more explicit name in PageAdmin.get_content_models which won't collide with a commonly used field name such as name.
Merge
Added Andromeda Yelton to AUTHORS.
Merge
Merge
Don't use ugettext_lazy for form field labels since Django will double-escape them. Closes #682.
Added to list of sites using Mezzanine.
Move case-insensitive keyword creation into KeywordManager, and allow for duplicate results. Closes #679.
Fix ADD_PAGE_ORDER. Closes #681.
Merge
Fix uses of next param for redirects where param exists but value is empty.
Fix invalid migration
Revert fix to #594 #677 - causes issues with status messages.
TagCloser - don't close br and image tags
Test changes to TagCloser