0033607: Visualization - Implementation of hardware occlusion queries

0033607: Visualization - Implementation of hardware occlusion queries

Hardware occlusion queries provides mechanism to answer whether or not
any pixels would be drawn. as instance it can be used as visibility filter
or acceleration for rendering complex scenes, by skipping occluded objects.

Graphic3d_ViewOcclusionMask : Provide way to access occlusion test results
for every graphical presentation per each defined view of the viewer

Graphic3d_OcclusionQuery : provides generic access to occlusion query
functionality.

OpenGl_OcclusionQuery: provides OpenGL implementation for occlusion query

Graphic3d_RenderingParams:  provides way to enable or disable occlusion query

AIS_InteractiveContext : reset view occlusion mask in new loaded objects

Each view invalidate its occlusion query results if camera has changed.