Make background have at least 4 colors

QuickHull3D requires at least 4 non-coplanar points in order to construct a convex hull. Noise was added to the background to meet this requirement.
Untrack the output of blob detection
Refactor drawChecker loop counters
Show magnified view around mouse position
Merge branch 'master' of https://github.com/chrismwendt/Document-Reconstruction