Register using identity claims

[ziogaschr]

This PR allows identity info to be used for profile registration.

It can be used for fixing issues #5 and #14

Sorry for doing 3 commits, but I had hard time on fixing the line endings and the whole file was being parsed as a single line. If you can advice me on how to work around, I am happy to make a new PR.

The actual code changes are at lines 42-72.

Another PR will follow showing how this can be used, although here is some example code for anyone interested which can be used in get_oauth_identity():

if(isset($result_obj['name'])){
    $oauth_identity['username'] = strtolower($result_obj['name']); //PROVIDER SPECIFIC: this is how Authentiq returns the name address
  }