Feature: Smart Pointers

[Michiel]

I've added a new wiki page to the project site. It describes the smart
pointer system of Mist:

http://code.google.com/p/mist/wiki/SmartPointers

Be sure to also look at the ACG slides of 12-05-2009 for a
demonstration of the implementation (slides 40-53):

http://code.google.com/p/mist/downloads/detail?name=cwi%20acg%2012-05-2009.pdf

Any comments on the pointer system itself should go here. Comments on
the wiki page (missing or confusing information) can go here, but can
also be put into a comment below the wiki page itself.