Update Main.py

Blending is now done in the main module as opposed to the transform module. Also, registration validation is added in this module
Update Transform.py

Removed blending, should be reserved for main module
Update Grade.py

Added output of structure 'answerMap' according to specification from google docs notes. Makes available a function for drawing circles based on this answerMap
Update ChangeLog.txt
Merge pull request #6 from superlaza/Registration-Validation

Registration validation