707 MultipleChoiceQuestion support for attempts

So far I've added support for initializing the mc question w/ the max attempts allowed, which includes updating the BricLayer to recognize the new maxAttempts activity property by copying it into the info domain so it can be referenced by configFixup.

I've also added support for getting and updating the attempts made from the attemptsMade property in the response object.

The submit button is correctly left disabled when the submitted answer was correct or if it was the last allowable attempt.

Currently there is untested code to display the correct answer when the last allowed attempt was incorrect. This needs the LocalAnswerMan to be updated to handle attempts, in order to test, which is the next thing I intend to do.