OCAF work

Started working at a layer that will hide the OCAF data structure from the application. These objects will expose properties and internally will work with TDF_label. Beside decoupling this layer will also allow adding extra features to the objects. Example: a rectangle object will know how to handle and update a Label hierarchy and will expose as properties the Name, the Color, the Vertexes, a width and a height. Any modifications on these properties will update the OCAF Label hierarchy that it holds internally.

Improved the PropertyGrid, made some refactoring, code cleanup and uploaded everything on SVN.