Added [Greyscale Brush]
Merge branch 'master' of https://github.com/ywangbc/COMP4411

Conflicts:
	impressionist.sdf
	ipch/impressionist-38c75e02/impressionist-fa0882cd.ipch
Implemented swapping views
Merge branch 'master' of https://github.com/ywangbc/COMP4411

Conflicts:
	ImpressionistUI.h
	impressionist.sdf
	ipch/impressionist-38c75e02/impressionist-fa0882cd.ipch