RelEx2Logic test cases

RelEx2Logic test cases.

This depends on https://github.com/opencog/relex/issues/98

To run tests using Maven:

    mvn test
    
To run tests using Ant:

    ant test-logic
    
or:

    ant test

Currently there are 3 test cases, all success:

![selection_411](https://cloud.githubusercontent.com/assets/24123/3537378/e3214928-081e-11e4-8d31-71fb285cd9d3.png)

We probably want more test cases to expand RelEx2Logic's knowledge :)