Visualization, TKOpenGl - support lighting + colored vertices within built-in GLSL programs

Within fixed pipeline combination of per-vertex color and lighting is possible, see OpenGl_VertexBuffer::bindFixed():

    case Graphic3d_TOA_COLOR:
    {
      theCtx->core11->glEnableClientState (GL_COLOR_ARRAY);
      theCtx->core11->glColorPointer (theNbComp, theDataType, theStride, theOffset);
      theCtx->core11->glColorMaterial (GL_FRONT_AND_BACK,GL_AMBIENT_AND_DIFFUSE);
      theCtx->core11fwd->glEnable (GL_COLOR_MATERIAL);

however within built-in GLSL programs this combination (Normals + Colors) is ignored.
Modified shader should use occVertColor in place of occFrontMaterial_Ambient(), occFrontMaterial_Diffuse(), occBackMaterial_Ambient() and occBackMaterial_Diffuse() to provide the same behavior.