Iteration over lists

[Richard A. O'Keefe]

I modified bengt's code to do each run in a new process.
The absolute times I got are of interest only on my machine,
but the relative times for N=10000 may be of interest:

Recursion:    1.4
RevRecursion: 2.9
MapFun:       2.2
ListCompr:    1.0

These are pretty much what you might expect.