[WIP] Travis support

Added lots of files copied from mdtraj to support travis. We'll see what happens ...
The `openmm` package is only on the `omnia` channel, so somewhere, you'll need a `conda config --add channels http://conda.binstar.org/omnia` in the `.travis.yml` or `devtools/ci/install.sh` to add the `omnia` channel so you can grab `openmm` if it is needed for testing.