ENH: Added debug color and fixed some small errors with colors

Base/Geometry/Mesh/imstkSurfaceMesh.cpp

Base/Geometry/Mesh/imstkSurfaceMesh.h

Base/Geometry/Reader/imstkAssimpMeshIO.cpp

Base/Materials/imstkRenderMaterial.cpp

Base/Materials/imstkRenderMaterial.h

Base/Materials/imstkTexture.h

Base/Rendering/RenderDelegate/imstkVTKRenderDelegate.cpp

Base/Rendering/RenderDelegate/imstkVTKRenderDelegate.h

...ring/RenderDelegate/imstkVTKSurfaceMeshRenderDelegate.cpp

...dering/RenderDelegate/imstkVTKSurfaceMeshRenderDelegate.h

Base/Rendering/VTKShaders/mesh.frag

Base/Rendering/imstkVTKCustomPolyDataMapper.cpp