speed up the get methods

[shawnlaffan]

Profiling indicates that much of the time in the heavy usage subs such as Geo::Shape::contains_point is spent fetching the X and Y coordinate values.

The ->X and ->Y methods serve as both setters and getters, so there is overhead in checking which purpose is being served at each call. Adding direct getters will therefore accelerate processing.

[shawnlaffan]

Methods and docs are in place.

Closing issue.