Merge pull request #504 from jnns/master

Improve searching in SocialAccountAdmin.
Be lenient and allow spaces in login field
Updated pt_BR translatations
Amazon HTTPS (closes #507)
Merge pull request #508 from dimiro1/patch-2

Updated pt_BR translatations
Added Flickr support (closes #499)
Typo at documentation: provider_media_js -> providers_media_js (closes #503)
Flickr py3 fix
Allow AJAX responses in signup view.
Merge pull request #521 from luizgpsantos/master

Allow AJAX responses in signup view.
Update README.rst

On an existing project, the SITE_ID information in settings.py is missing from the doc. If we follow step by step the documentation, there is an error when we try to reach the admin pages
Fixed KeyError on authentication without username
Merge pull request #526 from balkian/master

Fixed KeyError on authentication without a username
Added Bitbucket support (closes #530)
Added tests for Bitbucket provider (#530)
Adding Tumblr
Tumblr cleanups (closes #527)
E-mail case insensitive (partly addresses #517)
Added Foursquare Provider

First addition to another repo..
Please Check if everything ok!
Thanks!
Romanos Tsouroplis
Foursquare tweaks (closes #509)