updates to complexity pages

[David Meyer]

	Many people have asked to to update my complexity pages
	with a bit of theoretical background to to support some
	of the material there (in particular, percolation
	theory). So, as promised, I've updated

	  http://www.maoz.com/~dmm/complexity_and_the_internet 

	with a little (very little) bit of material on
	percolation theory. 

	Questions and comments on all of this very much welcomed,
	

	Dave