Merge pull request #3 from mapzen/dwn

Add Ellipse support. Some reformatting.
Merge pull request #4 from mapzen/dwn

Initial class for a graph identifier. Includes a hierarchy and Id.
Merge pull request #5 from mapzen/dwn

NodeInfo and Clipper2
Updated format
Merge pull request #7 from mapzen/gdg

Updated format
Merge remote-tracking branch 'origin/master' into dwn