started on the SceneGraph and SceneGraphNode classes
added linear transformation class
some more definitions for the scene graph
started implementing the scene graph
Refactored some of the smart pointer implementation
Added matrix multiplication to LinearTransformation
Started on tests for the scene graph
Created the inversion method of LinearTransformation
created more vector types
Fixed problem with unordered data structures, hashing and the SharedPointer class
started on the BoundingBox class
fixed a bug in the Vector types
Created the bounding box methods
added some useful macros for vector types
Fixed a naming conflict of BoundingBox and initialized BoundingBox in Image
converted SceneGraph to use weak pointers to data objects
moved LinearTransformation object to separate file and created several getBoundingBox methods
added getBoundingBox to surface renderer
created example in main.cpp for scene graph test
removed some legacy code