BUG: Textures can be swapped at runtime, normals can be modified at runtime

Examples/Rendering/RenderingExample.cpp

Source/Common/imstkColor.h

Source/MeshIO/imstkAssimpMeshIO.cpp

Source/Rendering/Materials/imstkRenderMaterial.h

...erer/RenderDelegate/imstkVTKSurfaceMeshRenderDelegate.cpp

...nderer/RenderDelegate/imstkVTKSurfaceMeshRenderDelegate.h

.../RenderDelegate/imstkVTKTetrahedralMeshRenderDelegate.cpp

...er/RenderDelegate/imstkVTKTetrahedralMeshRenderDelegate.h

Source/Rendering/VTKRenderer/imstkVTKRenderer.cpp

Source/Scene/imstkScene.h

Source/SceneEntities/Camera/imstkCamera.h

Source/SceneEntities/Objects/imstkVisualModel.cpp

Source/SceneEntities/Objects/imstkVisualModel.h