First implementation of the mrqblock max attempts feature
fix for int(None) in __nonzero__
Fix various issues and modified the main behavior of answers.
first try of LightChild data persistence
Fix lightchild data loading
Fix LightChild fields instanciation issue
Various fixes
Just used python native values and not LightChildField classes
A few corrections:

- Fix cursor pointer on checkmark icons
- Fix on success, checkmarks should all be displayed
- Fix don't increase counter when the mrq is completed successfully
Fix xml attribute set and modified the load_student_data
Improved LightChildField class and Fix load_student_data
Merge pull request #5 from aboudreault/mrq-max-attempts

Mrq max attempts