adding config library so users can set an appsecret if they like, precluding the need for passing in an appsecret proof. Also, type checking on fields to permit users to pass in a simple string of fields if they wish
updating readme
underping things
Moving graph url to config, switching to 2.0
Merge branch 'kadjar-master'
Merge branch '2.0' of github.com:kadjar/facebook.ex into kadjar-2.0
Merge branch 'kadjar-2.0'
Update myLikes & permissions API

- Add appsecret to fields as well there
- Update README
- Add @kadjar to contributors in the hex package desc.
Specify deps versions