A basic Thunk implementation. This is still buggy, but should be enough to discuss the basic design and API.

Hello @eford1, @skuwamoto, 

Please review the following commits I made in branch 'nick-lazy'.

57faaf480ca6fe098eeb369fc3a80b077e24e9d1 (2013-09-04 19:13:05 -0400)
A basic Thunk implementation. This is still buggy, but should be enough to discuss the basic design and API.


R=@eford1
R=@skuwamoto