Split previously merged fish
Extracted VideoReader class.
Added skip parameter to VideoReader.
Implemented segmentation algorithm using moving average background subtraction.
Added mixture of Gaussians background subtractor for segmentation.
Added composite segmentation algorithm.
Added algorithm for finding connected components.
Simplified AND operation in CompositeSegmentationAlgorithm.
Added notion of trackers with a CamShiftTracker that currently just draws boxes on the targets.  Changed find_connected_components to just return the large contours instead of drawing convex hulls.
Merge branch 'master' of github.com:drusk/fishcounter