Have each class in the segmentation appear as a separate layer

[2320sharon]

When segmentations are loaded onto the map each class for a segmentation should have their own layer.

• [x] Create a jpg for each class in the segmentation
• [x] Color each class a unique color
• [x] Add opacity controls for each layer
• [x] Remove segmentation layers when the next year's segmentation is loaded

[2320sharon]

This has been completed