Creates an indexed quad that you can draw.
var gl = require('webgl-context') var quad = require('gl-quad')(gl) quad.draw( myShader )
The passed shader is expected to have
``Creates a new quad with position and texcoord buffers.
var quad = createQuad(gl)``
``Draws the quad with a gl-shader.
If a shader is not passed, it's assumed that you've already bound a shader.