Support for inline shader props

[gre]

<GL.View
  shader={{ frag: "..." }}
  ... />

Use-case: shader editor

To do this, we need to introduce .remove(id) on GL.Shaders and implement it in implementations.

gl-react might do most of the work by handling the create / remove and providing shader id to the Surface implementations. remove is called when a previous inline shader is gone and when the Surface is destroyed (we somehow need to hook on this from gl-react side).