Manual axon/myelin segmentation and g ratio reporting

Quickly segment EM images of axons to find g ratio.

Simply draw a bounding box over the cell you wish to segment, then trace the inner and outer boundaries of the myelin. Returns stats table with label, centroids, area, perimeter, and g ratios (computed using both area and perimeter). Also returns labelled image, and axon and myelin masks to current Matlab path.