Update on Intro for 2.1

[Nate Klingenstein <ndk@internet2.edu>]

I'd offered to have something to the TC to look at for a new introductory section for the specification document restructuring by yesterday, but the Shibboleth project released an alpha during the last week.

I think I can help improve the quality of the first real release if I help test, so I'll be focusing my time there for a little while and the introductory section will be a little late.

I'm still on the line for this work item.  Thanks for your patience.