Improper design of some classes in Graphic3d

Some classes in Graphic3d package are designed in a poor way, violating basic principles of OO programming, such as incapsulation, and OCCT coding conventions. This causes troubles when wrapping these classes in C#:

- Graphic3d_BoundBuffer: fields Colors and Bounds are public pointers to internal buffer, should be private

- class (actually, struct) Graphic3d_Fresnel and enum Graphic3d_FresnelModel are defined in Graphic3d_BSDF.hxx

- Graphic3d_WorldViewProjState constructor and method Initialize accept argument Camera as plain C pointer, why not Handle? if it is used just as ID, it can be Standard_Address instead

- Graphic3d_StructuralManager uses map (Graphic3d_IndexedMapOfView) of plain pointers to Graphic3d_CView class, normally managed by Handle

- Method ActiveOwners() of the class SelectMgr_ViewerSelector uses direct instantiation of collection instead of typedef

- OpenGL_GraphicDriver: fields myLayerIds, myLayerSeq, myMapOfZLayerSettings are public