Update required Grails version to 2.3 due to call to GrailsClassUtils.getAllInterfaces(Object) introduced by commit 1fd365a531998deace8713ee48158c50a6a78a86
Merge pull request #12 from rlovtangen/requiresgrails23

Update required Grails version to 2.3 due to call to GrailsClassUtils.ge...