Currently the Array Viewer plots contours as lines, with each line in a constant color. It would be desirable for default contours to use N colored lines, where N is the number of levels drawn.

Also, it would be desirable for contours to support
- Flooded regions, both continuous and discrete. That is the color between levels would be matched from the bounding lines.
- Allow the levels of the contours to be defined by a vector dataset contained within the HDF file.