Connect with social networks account.

#6 
@zohar 

For now we have login with twitter. The module gives us two options:
creating a new account(which is what happened now) or bind a twitter account to an exiting user. 
We need something in between: if the there isn't a user with the email address of the twitter account create a new account. If there an account with the twitter email address bind the twitter account to the account.

I also looked up with two modules: fbconnect ad fb.
The fb module did create a login but if i logout on the Drupal site i also logging out on Facebook.com
The fbconnect gave me hard life.

What we need to cover is google account, linked in and maybe github.