[CI] Initial pass at new intro

[Hideaki Kimura]

> I checked in a new intro which I think addresses the concerns about 
> related work a little more clearly.  Please look it over and see what 
> you think -- Alex, I believe I've captured all the ideas you guys 
> mentioned in your mail, but I might have missed on or two.
> 
> I'm sure we will need to iterate on this, so pls read and comment!
Sure, I'm reading it and will comment within today.

> Also, there are some references to CT in the figures that I couldn't fix 
> -- if one of you could take care of that, that'd be great.
I'll do that.
-- 
Hideaki Kimura <hkimura at cs.brown.edu>