added support for auth_url so that it can support openstack swift

-a --auth env[CLOUD_FILE_AUTH_URL] support for auth end point, so that
it will support openstack swift
fix for empty zip filename when path ends in /
added fix for / as the directory name
fixed typo = -> ==
real fix for path = / call file root
filename root -> root.zip for /
Merge pull request #2 from benroeder/master

Added support for Openstack Swift, by adding the option to choose the auth endpoint