BlackAndWhiteImage initized in all white.
Added a method to ImageProcessingHelper to draw a list of objects on a
new image.
ImageProcessingRunner wraps the draw method on ImageProcessingHelper
with a video frame as the parameter.
NematodeVideoFrame no longer has a ProcessedImage object.
VideoFrameHelper's updateDisplayImage method now uses
ImageProcessingRunner to make a new display image.

Signed-off-by: Theo Chupp <chuppthe@msu.edu>