Experiment with showing boundary layer at lower zoom levels

The boundary style starts showing the boundary lines at zoom level 16. In practice, this is proving to be a little too close. Once you are at that zoom level, may regions do not fit onscreen.

This was set fairly high to prevent the lines from aggressively pulling focus from the trees. We should try 13, or maybe 12 and ensure that Philly, Edmonton, and LA all look good.
