lots of refactoring in the LukasKanadeOpticalFlow class
- exposed parameters to qt gui
- code is now understandable
- benchmark included

Signed-off-by: Marcel Schwittlick <marzzzel@gmail.com>
added another parameter to drawMotionField, so the cutoff for drawing the motionfield now has a maximum, too

Signed-off-by: Marcel Schwittlick <marzzzel@gmail.com>
closes #19

Signed-off-by: Marcel Schwittlick <marzzzel@gmail.com>