no way to control hand-off of temporary list files

Launchpad is experimenting with using lxc to drive transient VM-like instances for testing; the load-list parameter needs to refer to a local file inside the container, but files in the host OS /tmp are not handed into the transient containers (deliberately - container startup nukes /tmp :)). So some mechanism is needed to get the files into the container.

One way would be to teach testr about starting up/tearing down execution environments. Another is to allow setting TEMP within the .testr.conf