Using OpenGL "core" profile by default on macOS

Thanks to recent rendering code improvements, we can finally request “core” profile on macOS, to get latest OpenGL version (4.1 in my case) instead of being stuck with legacy OpenGL 2.1 on mac.

We request now a modern context on mac, both with TCastleWindow and TCastleControl. This applies to all our software — CGE editor, view3dscene, all your applications you build with CGE.