Initial travis file

This adds support for continuous integration builds with Travis CI.  To get this fully working Dr. Warburton will need to log into https://travis-ci.org and enabling Travis CI to build tcew/OCCA2.  You can see an example of it working here

  https://travis-ci.org/lcw/OCCA2

I disabled the pthreads example (`main_c` in addVectors) because it seems to hang.  It also hangs on my local system.