Fix CSRF token generation when cache is enabled, should solve #632
Added a reference to media library app

Just edited the README to add a reference to the Mezzanine media library app.
Add missing reference for link
Add code of conduct
New mezzanine-file-collections reference

mezzanine-media-library got renamed to mezzanine-file-collections. The reference was updated in this commit.
Added the bool setting ACCOUNTS_APPROVAL_REQUIRED, which defaults to False and when set to True, sets newly created public user accounts to inactivate, requiring activation by a staff member. Also added the setting ACCOUNTS_APPROVAL_EMAILS which can contain a comma separated string of email addresses to send notification emails to each time a new account is created and requires activation. Closes #417.
Document the new account approval feature.
Merge
Merge
Merge
pep8 fixes.
Better name for emails_list -> split_addresses.
Bump grappelli-safe version.
Fix thumbnail template tag for palette-mode images. Closes #636.
Added select_related for user in blog_recent_posts template tag.
Added apps.in to Sites Using Mezzanine
Fix lookup of initial data in from-builder forms, and correctly handle initial values for checkbox fields.
Allow forms-builder forms to contain template code for default values.
Provide more granular export filtering for multiple-choice fields in forms-builder export, eg matches/doesn't match any/all selected choices, and also allow range filters to use only one boundary.
Fix static_proxy to work with //host STATIC_URLs

STATIC_URL = '//mybucket.s3.amazonaws.com' would break the static_proxy prefix stripper, and therefore break tinyMCE plugins. This fix adds proper handling of generic-protocol hostnames to the static_proxy view.