Add Java version of Composition Kata

Some of the code isn't in Java style but I wasn't sure if that was part of the exercise to refactor also :) so I left it.

Example:
   
    public Collection<Measurement> filter(Collection<Measurement> measurements) {
        return measurements;
    }

Would usually be:

    public Collection<Measurement> filter() {
        return measurements;
    }

Where you return the field instead.

Let me know!