Travis support

As promised, here is support for Travis-CI, see it in action [here](https://travis-ci.org/richfitz/SPELT)

It works even if you don't have unit tests.  After merging (assume you merge!) edit the README.md file and swap `richfitz` for `nhcooper123` so that the little build icon thing points at your repo and not my fork.

If other people send you a pull request, Travis CI will let you know if it will break everything, which is a nice bonus.