Grab National Map tweaks from the nm branch.
Add specs.
Update CHANGES.md.
reject with a RuntimeError instead of throwing DeveloperError.
Run formatter.
Merge pull request #2040 from AnalyticalGraphicsInc/tweaksFromNationalMap

Tweaks from National Map
Merge remote-tracking branch 'origin/master' into faster-datasource-polylines

Conflicts:
	CHANGES.md