Colormap editor UI

[James-Crean]

The colormap editor ui needs to be moved around to more efficiently use the space it takes up.

In particular:

• The custom colors need to move up and close the gap
• The current color should move all the way to the left
• The RGB, HSL and hex, boxes should have their labels above the input and the inputs should be listed horizontally instead of vertically.

Resize the hue/contrast as needed.