0029074: Visualization, TKOpenGl - support Geometry Shader definition

0029074: Visualization, TKOpenGl - support Geometry Shader definition

Graphic3d_TypeOfShaderObject enumeration has been extended by Geometry shader object type.
OpenGl_ShaderProgram::Initialize() processes new shader object types when supported by OpenGL version.
Declarations.glsl has been fixed so that occFragColor is defined only for
Fragment Shader object only (by handling new FRAGMENT_SHADER macros).

Improved documentation of Graphic3d_ArrayOfPrimitives class.

vshader Draw Harness command has been extended to support definition
of Shader Object types other than Vertex and Fragment shader.