Do not query actual GraphicsMode.Default in DummyGLContext constructor. Doing so creates a temporary context, which should not be done when creating a dummy context.
Fixed issue [#993]: "Possible bug in GraphicsContext.CreateDummyContext()".
Improved CreateDummyContext logic to detect and use the context handle of the current thread or a specified handle.
Removed GetCurrentContext() methods from platform-specific context implementations (everything now goes through the relevant IPlatformFactories).
Added GraphicsContext.ErrorChecking property to temporarily disable error checking if necessary.
Error checking is now added to all functions in debug mode (the generator would miss specific CLS-compliant overloads before).
Added OpenGL 3.0 support for GLX contexts.
Added support for creating dummy contexts (useful if you are creating contexts from an external library).
Cleaned up unused and stale code.