4.2.0

Add ability to make the control transparent by setting GLWpfControlSettings.TransparentBackground to true. (@luiscuenca)
Change the dependency on OpenTK to be >= 4.3.0 < 5.0.0. (@NogginBops)
Add ability to pass a custom IBindingsContext in GLWpfControlSettings. (@Kaktusbot)
Add stencil buffer to the framebuffer. (@Svabik)
Fixed issue where remote desktop would fail due to having to use a software implementation of OpenGL.
Fixed so that KeyDownEvent and KeyUpEvent properly work in the control. (@BBoldenow)