PositionScheme for generic, geographic and projected position data

[navispatial]

To help implement #185 and #213 a new class is needed : PositionScheme with access to position and box factories:

  CreatePosition get position;
  CreateBox get box;

Following constant instances of PositionScheme:

• Position.scheme to create positions and boxes for any position data (geographic, projected or any other)
• Geographic.scheme to create geographic positions and boxes
• Projected.scheme to create projected positions and boxes

[navispatial]

Implemented in geobase 1.0.0.