Added support for running the tests under PyPy with tox
Added support for running the tests under PyPy with tox

This is a precursor to having them run under check and gate.

Change-Id: Ia512b68b5b47a88d5f7c1015cdf7151c322d293d

ironsmile/python-swiftclient,pratikmallya/python-swiftclient,sohonetlabs/python-swiftclient,zackmdavis/python-swiftclient,varunarya10/python-swiftclient,openstack/python-swiftclient,jeseem/python-swiftclient,iostackproject/IO-Bandwidth-Differentiation-Client,krnflake/python-hubicclient,citrix-openstack/build-python-swiftclient,iostackproject/IO-Bandwidth-Differentiation-Client,openstack/python-swiftclient,varunarya10/python-swiftclient,VyacheslavHashov/python-swiftclient,citrix-openstack/build-python-swiftclient,pratikmallya/python-swiftclient,sohonetlabs/python-swiftclient,VyacheslavHashov/python-swiftclient,jeseem/python-swiftclient,citrix-openstack-build/python-swiftclient,citrix-openstack/build-python-swiftclient,JioCloud/python-swiftclient,citrix-openstack-build/python-swiftclient,ironsmile/python-swiftclient,zackmdavis/python-swiftclient,JioCloud/python-swiftclient