Zooming/panning to a plotted route often leaves the start and/or endpoints out of the view extent

[mikewilburn]

The behavior of routing between two locations will adjust the map extent to add focus to the route that is drawn.
By default, the extent that is set will oftentimes leave either the starting point or ending points, or worse - both, entirely out of view.
We should adjust this to ensure both are in the view extent that's set.