Travis integration

- README.pod migrated to README.md for including travis build status image.
- Created .travis.yml file and tested with my fork and my travis account: https://travis-ci.org/eduardoj/Rex/builds/23397502 .
- Builds only on master and development branches.

Tip: image source will have to change from my travis account (https://travis-ci.org/eduardoj/Rex.png) to the official account in travis.

Looks fine to me in my fork: https://github.com/eduardoj/Rex