Update instagram media data for already loaded items
Bump django to 1.7

Needed fixes:
    - Moved slingsby.auth into slingby.users (auth name conflicted with
      contrib.auth)
    - Added default value for boolean fields
    - Renamed mimetype -> content_type in HTTPResponse()
Bump npm dependencies

We avoid bumping grunt-css-url-embed any further since after 1.0.4 it
requires a lot more hassle to install, since it needs to build native
binaries. As long as it works for us in this version, we'll stay here.
Add devlogin to menu if settings.DEBUG==False