fixes: #1166272 by Dave Cohen, John Klehm: support for facebooks oauth 2.  Mostly an upgrade of fixes from 6.x branch.

misc comments

Change the fb_cb url rewrite syntax.  Now use apikey instead of label.  This helps simplify fb_settings.inc.
multiple simplifications (fixes, lets hope) to fb_settings.inc.
fb_session.inc no longer needed (at least for time being).
more sanity checks and output in fb_devel.module

numerous changes, especially to session management and url rewriting. performance improvements and code simplification.

Disable install time requirements.  They prevent fb.module from being enabled, but allow modules which depend on fb.  This causes lots of grief.

Numerous changes to Drupal for Facebook.  Significant updates.  Manual configuration changes required.  http://drupalforfacebook.org/node/1055