[WIP] Parallels

A few notable crimes, but generally seems to get the job done.

Usage:
`py.test --appliance https://1.2.3.4 --appliance https://5.6.7.8`

A --verbose flag doesn't hurt, and it's a good idea to aim py.test at a few different appliances (it'll spread the test run out across as many processes as there are appliances).