Reorganized folder structure. Added Plane.

Inside of the lib/geo folder there is now a stand alone folder
for all of the library models such as Point and Polygon.

Created a Plane class that will be fully configurable. This plane will be used
as a starting point for many of the transformations and assumptions about how to
build geomeries.
Updated the Point class, adjusted Polygon.

Updated the Point class to also include a z value.

In tern this required some tweaking of the Polygon class.
Added #diameter and #circumference to Circle
Moved the Matrix class into Geo.

Moved the Matrix class to be part of the Geo module itself.

Cleaned up the Plane module with all specs now passing.