Native bindings to the OES_surfaceless_context extension.

Applications that only want to render to framebuffer objects should not need to create a throw-away EGL surface (typically a 1x1 pbuffer) just to get a current context. The EGL extension KHR_surfaceless_context provides a mechanism for making a context current without a surface. This extensions specifies the behaviour of OpenGL ES 1.x and OpenGL ES 2.0 when such a context is made current.