Set up a CI server to run the "short" test list

@jhamman suggested in #275

> Would it be possible at some point to get a subset of the CTSM tests that can be run on an arbitrary UNIX machine and to have those test be run on a Continuous Integration service like TravisCI or CircleCI? Just something to consider going forward, this tends to be standard for open-source projects these days and really helps maintain portability and usability of the model. A starting point may just be to build a standard compset with generic libraries.