FFP state management (light sources, matrices, clipping planes) has been
moved to OpenGl_ShaderManager for consistency with Programmable Pipeline.
OpenGl_Context::BindProgram() does not re-bind already active Program.
OpenGl_PrimitiveArray::Render() does not reset active Program at the end.
OpenGl_Context::ApplyModelViewMatrix() now checks if matrix differs
from already set one before modifying state in Shader Manager.
This allows avoing redundant state changes, matrix uploads onto GPU
and re-computation of inversed matrices.
NCollection_Mat4 has been extended with equality check operators for proper comparison.
OpenGl_ShaderManager - the tracking Material state has been added.
Removed unreachable states OPENGL_NS_RESMAT, OPENGL_NS_TEXTURE and OPENGL_NS_WHITEBACK.
Fixed resetting FFP material state after displaying GL_COLOR_ARRAY vertices;
the Material state within Shader Manager is now
invalidated within OpenGl_VertexBuffer::unbindFixedColor().
OpenGl_Workspace::ApplyAspectFace() - fixed invalidating Material State
when only Highlighting style is changing.
