#1050286: replace current_request() with request_path().  Also remove calls to deprecated fb_users_getInfo().

#979502 by a_c_m, Dave Cohen: session save handler patch.  Also, avoid unsetting registered user role.

sanity check to avoid infinite refresh

funcky redirect on logout only when needed.
experimental feature to grant role at runtime.

by aangel, Dave Cohen: moved fb_user_app table, which tracks users who have authorized apps, to its own module.

#870010 by aangel, Dave Cohen: mechanism to manually link accounts, if fb_user.module is not configured to do so autmoatically.

by aangel, Dave Cohen: stop using authmap table, use new table fb_user instead, for mapping local accounts to facebook ids.