Parallel figs

[mikewaters]

It would be useful to be able to run many figs in parallel, for instance to support a CI system similar in nature to drone.io (which fig appears to be partially, and thankfully, emulating in python).

One issue in particular is the fact that containers are removed when fig is run, to support workflows where the run configuration had changed (thanks @bfirsh).

I have no recommendations or patches, apologies!

[bfirsh]

A solution to this would be to make the project name configurable as a command line option (-p?). So for every instance of Fig you ran, you could give it a unique ID. E.g.:

$ fig up -d -p $BUILD_NUMBER
$ fig run web -p $BUILD_NUMBER ./test.sh

Related to #45.

[dnephin]

The project name was made configurable a while ago, so this is now possible (and I rely on it pretty heavily for CI).