Fix bug that was creating plateaus in the watershed dams.

The pseudocode is now included in the javadoc comments.
Remove unused variable.
When input image is 2D, show 2D connectivity in the GUI.

Notices the methods called to perform the segmentation are still the 3D ones.
Indent switch.
Make sure watershed lines are created in the output images.

Notice the watershed lines are now in true (0) black value in the output image. Before it was 255 with an inverted LUT.
Fix minimum size of the GUI to the preferred size after initialization.
Remove existing overlay in display image before creating output.
Add comment.
Still looking for bug that's creating plateaus in the watershed lines.

It looks like some pixels are added to the priority queue without a labeled neighborhood.