new authentication scheme supports, the following methods: user/passwd
(but save not clear passwd over wire), ssh, krb5, srp, globus and gui/uid
(like RFIO uses). Everything is documents here:
http://root.cern.ch/root/Auth.html.


git-svn-id: http://root.cern.ch/svn/root/trunk@7174 27541ba8-7e3a-0410-8455-c3a389f83636