Misleading opengl example

[Yamakaky]

extern crate gl;
extern crate sdl2;

fn main() {
    let sdl_context = sdl2::init().unwrap();
    let video_subsystem = sdl_context.video().unwrap();
    gl::load_with(|name| video_subsystem.gl_get_proc_address(name) as *const _);

    let window = video_subsystem.window("Toyunda Player", 800, 600)
        .resizable()
        .position_centered()
        .opengl()
        .build()
        .unwrap();

    unsafe{gl::BindVertexArray(0);}
}

It doesn't work ("gl function was not loaded"). gl::load_with must be run after the window creation (implicit dependencies yeay). You should at least mention it in the README.

[clooth]

Is this related to #497 ?

[Yamakaky]

Seems to, yes