Need automated tests to help find issues when setting up and starting unity8-lxc

There are many moving pieces to getting a Unity 8 session running in an LXC. Adding automated tests aimed at exercising the main parts of the whole process will help in detecting any issues.

Areas that should have automated tests:

1. Making sure unity8-lxc-setup can download the Ubuntu Next ISO and successfully create LXC config and the rootfs.
2. Making sure the unity8-lxc can start successfully and obtain an IP address.
3. Making sure the Unity 8 session itself can start from LightDM login.

Exercising those 3 areas will go a long way of assuring any issues will be detected along the way.

Ideally, there should be daily smoke tests for the intended targets as package updates to the host and changes in the ISO itself can cause failures. Intended targets are supported Ubuntu release and the current development release as hosts and the daily Ubuntu Next ISO found at http://cdimage.ubuntu.com/ubuntu-desktop-next/daily-live/current/ as the LXC rootfs.