Start streamlining the GeoJSON api.
Ongoing GeoJSON cleanup

1. Streamline Sandcastle example
2. Expose basic graphics objects instead of entire entities for default options
3. Add CZML Sandcastle example to the `DataSources` label.
Ongoing GeoJson cleanup.
Update CHANGES
Tweak CSS.
Merge remote-tracking branch 'origin/master' into geojson
Remove unecessary and invalid custom property definition.
Merge remote-tracking branch 'origin/master' into geojson
Changes after review.
Merge pull request #1952 from AnalyticalGraphicsInc/geojson

GeoJSON cleanup