title: Deleting WebGL contexts
body: <p>I have a page that is using many many webgl contexts, one per canvas.   canvases can be reloaded, resized, etc. each time creating new contexts.   It works for several reloads, but eventually when I try to create a new context it returns a null value.   I assume that I'm running out of memory.</p>
  
  <p>I would like to be able to delete the contexts that I'm no longer using so I can recover the memory and use it for my new contexts.   Is there any way to do this?   Or is there a better way to handle many canvases?   </p>
  
  <p>Thanks.</p>