Multiple exit code handling fixes call() on POSIX now always gets the exit code of the process. force_zero_exitcode now has no effect if the process got killed by a signal.

import sys
if sys.version_info[0] >= 3:
	from zipfile31 import *
elif sys.version_info[1] >= 7:
	from zipfile27 import *
else:
	from zipfile26 import *