WICKET-663 enhance ichoicerenderer with id->choice object lookup

Restore IChoiceRenderer as discussed at http://markmail.org/message/nek75o5eftmpkobo
WICKET-5538 When using Component.setDefaultModel, only detach the previous model if the new one is different

(cherry picked from commit 6f791bd8298aab764774938e6b90f7bd1305830d)