remove DatabindingApi
fix failing test

In Grails 2 the "properties" property was made writeable for all classes which were used as command objects.  I think this was accidental/incidental and not really intentional.  The previous commit caused tests to fail which pointed this out.  If we really want the "properties" property to be writeable we can move the setProperties method out of grails.artefact.Domain and into some common trait which is applied to domain classes and command objects alike.
move test and eliminate runtime compilation

The test needed to be moved to a project which has dependencies required for compile time trait injection for domain classes