Merge pull request #261 from momamene/master

Add Kakao backend
Added LoginRadius backend.
PEP8 and logic simplification
Merge branch 'grepme-master'
added new backend classes for Facebook that use the Open Graph 2.0 endpoints
Settings to override default scope/attrs and docs about them. Refs #258
Merge pull request #264 from dryan/facebook-opengraph-2.0

Support for Facebook Open Graph 2.0
PEP8 and docs about Facebook Graph 2.0 backends