Restructure Layer Style Editor

[jng]

The existing Maestro Layer Style editor is a woefully inefficient use of precious vertical screen real estate.

Instead of rendering out each scale range as a separate control, we can compress this by displaying the scale range as a list. Selecting a scale range in this list will then create and load the corresponding UI control to edit the style rules in this scale range.

This change is really to make the composite symbolization stuff easier to integrate.

[jng]

Fixed r5941 and r5942