Added IndexError exception in response to __getitem__ failure.
Added __iter__  methods to various math collection objects.
Added a generic ItemEditorCreator to the editorfactory module.
Refactored the PropertyModel to display nested properties.
Fixed hasData check.
Added python hash method to math objects.
Added wrappers methods around signal emitters for greater control.
Removed unused import.
Connected MainWindow to the SceneGraphModel's Data Changed signal.
Converted math 'data' property into an accessor method
Removed redundant import from camera.py
Updated Matrix4x4 to created instances using the instance's class definition.
Connected the model's dataChanged signal to the glwidget's update method.
Added a __setitem__ to math objects and updated accessor properties accordingly.
Convert math objects to QObject and exposed a dataChanged signal.
Made minor correction in AbstractPropertyItem's comments.
Made minor correction in AbstractDataTreeModel's comments.
Updated dev virtual environment from Python 3.3 to Python 3.4
Refactored TransformationNode into a base class of PrimitiveNode.

Related Changes:
* Added scenegraph\object.py and scenegraph\viewport.py.
* Split SceneGraphItem in SceneGraphNode and SceneGraphRoot.
* Converted SceneGraphItem to AbstractSceneGraphItem.
Updated virtual environment path in QtDesigner and PysideRCC scripts.