Travis ci integration

Next step - automatic testing. Things in current PR:

1. Restructured project folders
2. Example target removed - it was empty anyway.
3. Added OS X unit tests target
4. Added Travis CI configuration file and Rake test runner.

Comments.

For now tests will be run on 32-bit iOS and 64-bit Mac OS X. This allows us to catch any platform-specific bugs, or bugs with 32-64-bit types difference. Test runner uses [shenzhen Ruby gem by Matt Thompson](https://github.com/nomad/shenzhen) to improve test output. To run tests on both platforms - simply cd to EasyMappingExample directory and run `rake`.

/cc @lucasmedeirosleite