refs #1166272 by funkym, Dave Cohen: correctly check the map_account setting, which is checkboxes (not radios like it once was).

fixes #1273828 by Dave Cohen, tpainton, Jolidog: facebook gets all weird when classname is fb-login-button.

Added fb_api_batch() helper (but likely to change it in the near future, work in progress).

Also, unrelated change to _fb_user_fbu URL param.

#1075590 by perceptum, Dave Cohen: fix sql for fb_user_get_local_friends

#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.