fix incoming redirects from facebook app center
Wordpress resource owner requires access token to be sent as header when calling API
Fixed PHP error on $session variable in redirectToService action

$session contained a boolean value because of the call to start(). But the session variable is expected to be the session object a few lines after the call.
Fix previous commit
Merge pull request #487 from stloyd/bugfix/fb_app_center

[Bugfix] fix incoming redirects from facebook app center
Merge pull request #491 from stloyd/bugfix/wordpress

Wordpress resource owner requires access token to be sent as header when calling API
Added missing 'prompt' parameter for Google

The 'prompt' parameter could be defined but was ignored when constructing the authorization URL.
Merge branch 'hwi/0.3'