Add x86_64-darwin build, and fix the platform dependent builds, as the system wasn't passed through properly.
Minor enhancement to show-physical of a backup, make the disk value strict to allow easier inclusion to another network.
removing unused imports
pep8: whitespaces (E201, E202, E203. E231, E225)
pep8: blank lines (E301, E302, E303)
rest of pep8 fixes