Adopt an Ubuntu 14.04 style interfaces.d/ directory
Add functional external network and floating IPs to testenv
Setup neutron router external interface

Import current version of neutron_network and neutron_router_gateway ansible modules patched to support cacert.
Merge pull request #285 from blueboxgroup/interfaces.d

Adopt Ubuntu 14.04 style /etc/network/interface.d/ and extend test suite