0024228: TKOpenGL - destroy GL context at view close

0024228: TKOpenGL - destroy GL context at view close

- OpenGl_Display - release GL resources correctly on closing views
- OpenGl_AspectFace, OpenGl_AspectText, OpenGl_AspectLine, OpenGl_AspectMarker - initialize OpenGl resources on demand, when context is available.
- Graphic3d_TextureRoot - use const modifier for GetId method to avoid asynchronous resource state at OpenGl.
- Do not call OpenGL functions if no active GL context has been left
- Reset thread's context before deletion for Mesa WNT