Modify MeshVS to support smooth and flat shading

Documentation remark, added by Author 2005-08-29 12:59:51:

Improvements:
Two types of the mesh visualization in shading mode were added in MeshVS:

To enable default shading mode you should set "MeshVS_DA_Reflection" flag of
"MeshVS_Drawer" to "Standard_True" and "MeshVS_DA_SmoothShading" to
"Standard_False"

To enable smooth shading mode you should set "MeshVS_DA_Reflection" flag of
"MeshVS_Drawer" to "Standard_True" and "MeshVS_DA_SmoothShading" to
"Standard_True"

To enable flat shading mode you should set "MeshVS_DA_Reflection" flag of
"MeshVS_Drawer" to "Standard_False" and "MeshVS_DA_SmoothShading" to
"Standard_False".
Modified entities:
In MeshVS package:
MeshVS.cdl - new flag "MeshVS_DA_SmoothShading" was added.
MeshVS_Mesh.cxx - was modified.
MeshVS_MeshPrsBuilder.cxx - was modified.
MeshVS_MeshPrsBuilder.lxx - was modified.