sanity check for 3.x style prefix configuration on canvas pages callbacks.

Validate with app secret, when available.

reset session and reload when user tokens become invalid (user logs out of facebook)

Helper function to determine if user is currently connected.
Fixed some startup logic that was order dependent.

Fixes #2159907: Facebook app ids are integers, and integers are not safe array indicies in Drupal's js settings.

Minor doc fixes.
Fixes to fb_opengraph

Cleaned up PHP notices

Name changed to fb_opengraph.module.

Functional, but still in progress.

misc debug cleanup
misc admin form improvements

fb invite form as render element, easily added to any drupal form.

No more fb_app(), replaced with fb_get_app().

default access_token for graph() helper function.
fql() helper function.