Cleanups after new route snapper

[dabreegster]

• The markers cover up the panel (fixing the z-indexing is hard)
• Restore undo functionality
• Hover on a line to immediately start adjusting it?
• Add a button to clear/reset the route?
• Move the snapped waypoints to the position where they snap after the user releases the marker?
• When converting from snapped to freehand, should we automatically insert the nearest snapped points to make the user do less work?
• Disable the free/snap controls in drag mode; display the hint to click instead for toggling?
• Put red/blue next to the free/snap radio?
• Revisit EditMode's unsavedFeature; it can be done much more simply now