RTL: fix position of help icon in filter_horizontal m2m widget

--HG--
extra : rebase_source : a201efaee395d8d3bff8e88799c30830346a9e2b
Only add input-xlarge on inputs without a class attribute, fixes #643
Replaced the BLOG_URLS_USE_DATE setting with a new BLOG_URLS_DATE_FORMAT setting - it can contain the string year, month, or day, which controls the date granularity in blog post URLs.
Editable settings refactor - this change is to clear up confusion around editable settings being defined in a project's settings module. Previously when this happened, the settings.py module value would only serve as a default, which would be superceded by the db editable value as soon as the settings admin form is first saved. To address this, this change means that editable settings defined in the project's settings.py module now mark the setting as not editable, so it will always be the value used. We also include some handling for the migration case so that even with this change, editable settings already in the db that have a settings.py value defined will still use the db value and provide a warning.
Revert the handling for still using db values for editable settings with settings.py values defined, since it basically defeats the purpose if a settings.py value is added once a project is live.
pep8 fix
Added INLINE_EDITING_ENABLED setting
New INLINE_EDITING_ENABLED setting doesn't need to be editable.
Added Jeff Fein-Worton to AUTHORS.
Fix lost russian translation in accounts
Merge
Don't force lowercase keywords. Closes #647.
Allow blog feed title and description to be overridden.
Use callable description in atom rss feed.
Fix age display: use a blocktrans instead of {% trans 'ago' %}

In some languages, like french "ago" is a preposition, so doing
something like "{{ value }} {% trans 'ago' %}" will not work, we have to
use a blocktrans.
Properly escape comments in comment_filter template tag.
Bump grappelli/filebrowser versions.
Version bump to 1.4.6
Added tag 1.4.6 for changeset 94f1427035e1
Update auto generated CHANGELOG, requirements, settings docs.