ActivityDefinition InteractionType

[olivergurnell]

ActivityDefinition has been extended to include: interactionType correctResponsesPattern choices scale target step

This as been based on the work carried out by Paul Carpenter and is my first GitHub submission.

[brianjmiller]

Sorry for the delay on this, I'm trying to give our OSS libs some love.

[cawerkenthin]

This code works. I did follow @brianjmiller suggestion that constant names should be capitalized, and changed the code to use the defined constants.

[ghost]

I need the features provided by this request, why is this yet to be merged?

[garemoko]

@peturingi this needs somebody to work through the PR and make the changes as suggested by @brianjmiller in his review, then probably open a new PR with those changes included.

[ghost]

@garemoko @brianjmiller I made the changes and created a new PR.