Not reinitializing vao
In the guide here http://onrendering.blogspot.no/2011/10/buffer-object-streaming-in-opengl.html it shows that after orphaning the buffer you need to reset your vao. In sketch currently it is only rebound.

instead something like this should be added to glkit
```
(defun reinit-vao (vao)
  (with-slots ((vao-type type) id vbos vertex-count) vao
    (with-slots (groups) vao-type
      (loop for group across groups
         as vbo-offset = 0 then (+ vbo-offset vbo-count)
         as vbo-count = (vao-vbo-count group)
         as vbo-subset = (make-array vbo-count :displaced-to vbos
                                     :displaced-index-offset vbo-offset)
         as attr-offset = 0 then (+ attr-offset attr-count)
         as attr-count = (vao-attr-count group)
         do (loop for i from 0 below (vao-attr-count group)
               do (%gl:enable-vertex-attrib-array (+ i attr-offset)))
           (vao-set-pointers group attr-offset vertex-count vbo-subset)))))
```

and this be called from start-draw, as in:

```
(defun start-draw ()
  (%gl:bind-buffer :array-buffer 1)
  (%gl:buffer-data :array-buffer *buffer-size* (cffi:null-pointer) :stream-draw)
  (setf (env-buffer-position *env*) 0)
  (kit.gl.vao:vao-bind (env-vao *env*))
  (kit.gl.vao::reinit-vao (env-vao *env*)))
```

This has been working but I think only because there is only one vao. 