Renamed topiarist.implement() to topiarist.hasImplemented(), in
preparation for the introduction of a new topiarist.implement() method
that can be used before the interfaces methods have been defined.
Re-introduced a topiarist.implement() method, which this time can be
used before the interface has been fully defined.
Merge pull request #16 from BladeRunnerJS/improve-br-implement

Improve br implement