Code where DownCast was applied to Handle of the type being not a base class of the target one is revised and (hopefully) corrected.
Code corrected following review remarks
GeomConvert::CurveToBSplineCurve() is called even for b-spline curves to ensure that result is non-periodic
Check for conic is corrected
License statement text corrected; compiler warnings caused by Bison 2.41 disabled for MSVC; a few other compiler warnings on 54-bit Windows eliminated by appropriate type cast
Wrong license statements corrected in several files.
Copyright and license statements added in XSD and GLSL files.
Copyright year updated in some files.
Obsolete documentation files removed from DrawResources.
