[security-services] Revised SAML Basics presentation

I revised my presentation because I'll be delivering it at MITRE this 
week.  Everyone, please let me know if you have comments.  I used core-25 
and bindings-09 as the basis for the information here, though the speaker's 
notes do try to reflect trends in technical decisions that we've been 
making.  Jeff/Joe, feel free to link to this from the outreach section of 
the website.

	Eve