This benchmark was taken just after I changed the internal
PML object from a hash to a array reference. There is a 
very small speed improvment. I think that the real improvment 
is probably a little better because my bechmark script sucks.

-- Peter

100 calls to PML took: 17 wallclock secs ( 6.89 usr  0.05 sys +  0.00 cusr  0.05 csys =  0.00 CPU)
