E202,E301 - Refactor assignment_controller; Microtasks & Micropayments

Project E202: Refactor assignment_controller

Authors:  tfgregor, smalexa2, che

Class: assignment_controller.rb

Refactor List:

* Basic refactoring of assgnment_controller
  - Moved out common code into separate methods
  - Broke long methods into shorter methods (create, update)
  - Simplified code where possible

* Added functionality to be able to change Rounds of Review in edit mode (this also allows adding other deadlines not previously created)

* Assignment due days are modified to be listed in chronological order

* When copy an existing assignment, the new assignment will use a new location instead of using the same location

* Bug fix
  - Fix for Rounds of Reviews not working in IE8
  - Fix several method not found errors that were caused by entering invalid information
  - Added dynamic display actions for rubrics and deadlines