Add Travis CI for automated tests

[mattsches]

What is this feature about (expected vs actual behaviour)?

Proposal/Feature Request: Add automated tests on travis-ci.org.

Advantages are: The project can be tested against different versions of PHP, tests of PRs are automatically run, etcetc. plus you can add a nice "build passing" badge to the repo.

How can I reproduce it?

See Travis configuration of my fork: https://github.com/mattsches/DoctrineRestDriver/blob/master/.travis.yml and the respective builds on Travis CI https://travis-ci.org/mattsches/DoctrineRestDriver

Does it take minutes, hours or days to fix?

Minutes, once you are familiar with how Travis CI works.

Any additional information?

You could also add more or other services like scrutinizer-ci.com or coveralls.io to emphasize the quality of the project.