0026886: Visualization, TKV3d - eliminate global variables

0026886: Visualization, TKV3d - eliminate global variables

- AIS_InteractiveContext - create new dummy class field to have an empty TopoDS_Shape object.
- AIS_Point, PrsMgr_PresentableObject - rename static variables to local function variables.
- AIS_Shape, SelectMgr_SelectableObject - remove unused static variables.
- Graphic3d_MaterialAspect, V3d_Viewer - make global static variables as constant.
- V3d_View - move global variable zRotation to class field.
- Move a variable theCurrentSelection as a field of AIS_InteractiveContext and AIS_LocalContext classes. Multiple selection is not used now, so each Context have an own selection.
- Move myStructGenId from Graphic3d_StructureManager to Graphic3d_GraphicDriver for identifying the structures in the driver.
- Move default variable (no shading light) from static value to the class field of OpenGL_View.
Porting note:
- Static methods of AIS_Selection is not used now. Methods of
  AIS_InteractiveContext::InitSelected(),::MoreSelected(),::NextSelected()
  should be used instead of static methods of AIS_Selection.