GeoJson fixes and cleanup

1. Automatically set `perPositionHeight` to true if a polygon contains altitude values.
2. Remove `sourceUri` parameter from the geometry functions since they are no longer used (and haven't been for a while).
3. Move polygon creation code into a helper function to de-duplicate code that was in both `processPolygon` and `processMultiPolygon`
4. Added specs and updated CHANGES.
Delete uneeded sandcastle example.

Fixes #2146
Merge pull request #2163 from AnalyticalGraphicsInc/delete-profile-halfdome

Delete uneeded sandcastle example.
Merge pull request #2148 from AnalyticalGraphicsInc/geojson-heights

GeoJson fixes and cleanup
Merge remote-tracking branch 'origin/master' into maki