WS_CLIPCHILDREN and WS_CLIPSIBLINGS appear to cause flickering on
specific video cards. OpenGL appears to work correctly without these, so
we'll disable them to return to OpenTK 1.0 behavior.
SDL does not currently support embedding into Windows Forms (this is an
upstream limitation.) To ensure that existing WinForms applications
continue to function even if SDL is installed, GLControl will now try to
initialize OpenTK with a native backend. The user can still override
this behavior using OpenTK.Toolkit.Init(ToolkitOptions), as normal.
* GLControl.cs: More defensive checks for null GraphicsModes.
Set flags, context version and GraphicsMode before calling
InitializeComponents(), as the latter might cause the context to be
created (and we need this information before creating the context).
Fixes ArgumentNullException on Linux.
members are accessed (issue [#1141]: "Unhandled exception in
GlControl possible bug in rev 2207"). Throw ObjectDisposedException
if public members are accessed after the GLControl has been
disposed. Force the create/recreation of the control if a public
member is called and the control handle or context does not exist.
