exposes the wide array of authentication possibilities.
Authentication now has it's own page separate from other variables.
Most of this work was done by Petri Asikainen <paca@sci.fi>, who started
these changes off.
I've done some cleanups and additions which is why I'm checking it in.
It's all working pretty well at the moment but could use some testing.
Thanks, Petri! :-)
pluggable modules in the 'auth' directory.
Everything is done through authentication_user_login in lib/moodlelib.php
As well as the old default "email" confirmation, I added a new type of
confirmation "none", which basically does no confirmation at all.
