Support of display for supervoxels (sv). Show borders of sv; indicate whether the gradient of the image is in agreement with sv borders

[jakubMitura14]

Success when
Given an integer mask where a unique integer value will encode information about a single supervoxel and an underlying 3d medical image user will have the option to overlay the original image with the borders of the superpixels where adjacent borders will have different colors, or show those borders on the background of the image convolved with edge filter, for example, Sobel filter

[divital-coder]

Addressed in GSOC PR