Geospatial work: implemented GeoLocation node

This adds support for the GeoLocation node in Geospatial.js

One caveat is that the node derives from X3DTransformNode and not from X3DGroupingNode as implied by the spec.
However, the GeoLocation functionality is in effect a specialized Transform node.

Here are two examples which show the use of the node:

https://googledrive.com/host/0BwIhFzkLaQ9XOFd2ZFlTNnAyMkE/A4_GeoLocation.html
https://googledrive.com/host/0BwIhFzkLaQ9XOFd2ZFlTNnAyMkE/GeospatialCoordinateAxesNsewExample_updated.html