Add travis CI integration
    
    Add .travis.yml configuration, allowing anyone to run sanlock tests in
    travis.
    
    To enable to tests in travis:
    - Fork sanlock on github
    - Enable Travis-CI service
    - Visit https://travis-ci.org/profile and enable the tests for your
      username/sanlock
    
    After this setup, each time you push to your sanlock fork, travis will
    run the tests with your patch using travis standard build environment
    (Ubuntu Trusty).
    
    Here is an example travis build on my sanlock fork:
    https://travis-ci.org/nirs/sanlock/builds/325674436
    
    Since sanlock is developed mainly on Fedora, running the tests on Ubuntu
    ensure that we are compatible with Debian based distros, and will reveal
    portability issues quickly.
    
    Signed-off-by: Nir Soffer <nsoffer@redhat.com>