Clarify notes on drawing dynamic textures during context loss.
Allow `Shader` to initialize and operate during context loss.
Improve resize handling on context loss and recovery.
All textures and shaders should automatically recover from WebGL
context loss.
Dynamic textures will lose their contents, unfortunately, as the texture
was stored on the GPU.
Frame buffers still have some bugs to work out.
This is mostly hooking up gl calls to look inside the wrapper.
A few other things have changed.
Spector metadata is set the new way.
`Frame` changed `glTexture` to a getter, simplifying bookkeeping.
`LightPipeline` and `Plane` use standard methods to create textures.
`WebGLRenderer` maintains a list of wrappers, and automatically
manages it through `createTexture2D` and `deleteTexture`. The update
methods `updateCanvasTexture` and `updateVideoTexture` have been
delegated to the wrapper.
* The `WebGLRenderer.currentActiveTexture` property has been removed.
* The `WebGLRenderer.startActiveTexture` property has been removed.
* The `WebGLRenderer.tempTextures` property has been removed.
* The `WebGLRenderer.textureZero` property has been removed.
* The `WebGLRenderer.normalTexture` property has been removed.
* The `WebGLRenderer.textueFlush` property has been removed.
* The `WebGLRenderer.isTextureClean` property has been removed.
* The `WebGLRenderer.setBlankTexture` method has been removed.
* The `WebGLRenderer.setTextureSource` method has been removed.
* The `WebGLRenderer.isNewNormalMap` method has been removed.
* The `WebGLRenderer.setTextureZero` method has been removed.
* The `WebGLRenderer.clearTextureZero` method has been removed.
* The `WebGLRenderer.setNormalMap` method has been removed.
* The `WebGLRenderer.clearNormalMap` method has been removed.
* The `WebGLRenderer.unbindTextures` method has been removed.
* The `WebGLRenderer.resetTextures` method has been removed.
* The `WebGLRenderer.setTexture2D` method has been removed.
* The `WebGLRenderer.pushFramebuffer` method has had the `resetTextures` argument removed.
* The `WebGLRenderer.setFramebuffer` method has had the `resetTextures` argument removed.
* The `WebGLRenderer.popFramebuffer` method has had the `resetTextures` argument removed.
* The `WebGLRenderer.deleteTexture` method has had the `reset` argument removed.