add a travis script

Hi,

I just enabled this awesome [travis continuous integration](https://travis-ci.org) service to your project.
Here are the step to configure the service to make it work with your repository:
- Sign in with your [github](https://github.com) account
- Enable your repository on your [profile](https://travis-ci.org/profile)
- Merge my pull request

You then should be able to see your building status. Have a look on mine: https://travis-ci.org/MartinDelille/hippomocks

Next step: adding a README with a build status badge (I'll send you another PR if you want).

Feel free if you have any question!