Added another fill color.

Turns out that my employer uses 'probe area' and 'project area' (or something)
at the same time, so I might end up changing the types of my data again.
Fixed MultiPolygon/MultiLineString event callbacks.
Added 'draggable' property to map options.

I should have thought of that 15 years ago: It was painful to distinguish
between shapes and similar shapes with holes in them, if they are stacked on
top of one another. I have to work something out for MultiPolygons, though.