BED cleanup, use standard python instead of pythonpy
BED cleanup, use standard python instead of pythonpy

Tries to report cleaner error messages without as much command line magic.
https://groups.google.com/d/msg/biovalidation/lEg8j8-ZLpU/gyd10zpUBAAJ

a113n/bcbio-nextgen,a113n/bcbio-nextgen,lbeltrame/bcbio-nextgen,lbeltrame/bcbio-nextgen,chapmanb/bcbio-nextgen,lbeltrame/bcbio-nextgen,vladsaveliev/bcbio-nextgen,vladsaveliev/bcbio-nextgen,chapmanb/bcbio-nextgen,a113n/bcbio-nextgen,vladsaveliev/bcbio-nextgen,chapmanb/bcbio-nextgen