Disable the default login and register form of omniauth identity.
1. Add the ablity to sigin by third party services.
2. Change the signup process if user signup by third party servies.
1. Add bind and unbind weibo authentications feature.
2. Refactor this part, move the weibo authentcations related function
from verify to authentications.
Fixed the failed spec.
Make the weibo login configurable.
User can add identity if login from third party service.
Some refactor for the weibo login.
Add 'login via weibo' button on index page.
Merge branch 'master' into third_party_auth
Add tests for authentications related controllers.
Add the spec for #create_auth_for_identity and #remove_auth
Merge pull request #305 from peatio/third_party_auth

Add the function for login from third party services