ENH: Added texture manager and render material class

Base/Geometry/CMakeLists.txt

Base/Geometry/Mesh/imstkSurfaceMesh.cpp

Base/Geometry/Mesh/imstkSurfaceMesh.h

Base/Geometry/imstkGeometry.cpp

Base/Geometry/imstkGeometry.h

Base/Materials/CMakeLists.txt

Base/Materials/imstkRenderMaterial.cpp

Base/Materials/imstkRenderMaterial.h

Base/Materials/imstkTexture.cpp

Base/Materials/imstkTexture.h

Base/Materials/imstkTextureDelegate.h

Base/Materials/imstkTextureManager.h

Base/Rendering/CMakeLists.txt

Base/Rendering/RenderDelegate/imstkVTKRenderDelegate.cpp

Base/Rendering/RenderDelegate/imstkVTKRenderDelegate.h

...ring/RenderDelegate/imstkVTKSurfaceMeshRenderDelegate.cpp

...dering/RenderDelegate/imstkVTKSurfaceMeshRenderDelegate.h

Base/Rendering/imstkVTKRenderer.cpp

Base/Rendering/imstkVTKRenderer.h

Base/Rendering/imstkVTKTextureDelegate.cpp