Task module response prototype

Setup table structure and restructured some task modules/forms to store student responses in a table consistently. This also allows the task content to be dynamically displayed and maintained more consistently, while allowing the creation and reuse of modules.
Along the lines of my previous comment, I think a future pass on this code may get rid of the explicit special cases for file and user_confirm.  Instead, we'll probably just have a list of TaskSections and the file and user_conform views will just be another module that we put in a TaskSection.