message: fixing destroy()
diff: @@ -230,14 +230,14 @@ export default class FilterSystem extends WebGLSystem
  shader = new Shader(this.gl, filter.vertexSrc, filter.fragmentSrc);
  filter.glShaders[renderer.CONTEXT_UID] = this.shaderCache[filter.glShaderKey] = shader;
  + this.managedFilters.push(filter);
  }
  }
  else
  {
  shader = filter.glShaders[renderer.CONTEXT_UID] = new Shader(this.gl, filter.vertexSrc, filter.fragmentSrc);
  - }
  -
  this.managedFilters.push(filter);
  + }
  // TODO - this only needs to be done once?
  renderer.bindVao(null);
  