pre
moved
Multiprocessing added

Tests for /zport traverse only:

$ time python findposkeyerror.py /zport

real    0m23.052s
user    0m11.346s
sys     0m6.446s
$ time python mp-findposkeyerror.py

real    0m18.712s
user    0m24.753s
sys     0m9.334s