Output risk maps on external windows

[Zach10a]

At the moment #77 looks like it will only allow the top risk map on the left-hand layer list to be shown on the map. This is obviously not an ideal situation, and it seems that each different risk/path layer combination may need to be observed. The ideal scenario is that each pathfinding layer has the ability to be brought up onto a new popup window, where it will show the path and relevant risk map layer.

[aliaksei135]

Would also fix the state being overwritten in the main window. Only thing to watch for is the DataWindow follows the popup instead of staying with the main window to ensure the state is consistent if the layer is regenerated in a new window