* The `WebGLRenderer` has 4 new properties: `maskTargetFramebuffer`, `maskSourceFramebuffer`, `maskTargetTexture` and `maskSourceTexture`. These are the new global locations of the mask framebuffers.
* `WebGLRenderer.createBitmapMask` is a new method that internally creates the Bitmap Mask framebuffers.
* `WebGLRenderer.clearBitmapMask` is a new method that internally clears the existing Bitmap Mask framebuffers, called as part of a resize event.
* `WebGLRenderer.enableBitmapMask` is a new method that starts the process of using the mask target framebuffer for drawing. This is called by the `BitmapMaskPipeline`.
* `WebGLRenderer.drawBitmapMask` is a new method that completes the process of rendering using the mask target framebuffer. This is called by the `BitmapMaskPipeline`.
* The Light Pipeline no longer creates up to `maxLights` copies of the Light shader on boot. Previously it would then pick which shader to use, based on the number of visible lights in the Scene. Now, the number of lights is passed to the shader and branches accordingly. This means rather than compiling _n_ shaders on boot, it now only ever needs to create one.
* You can now have no lights in a Scene, but the Scene will still be impacted by the ambient light. Previously, you always needed at least 1 light to trigger ambient light (thanks jstnldrs)
* The `Light.frag` shader now uses a new `uLightCount` uniform to know when to stop iterating through the max lights.
* The `LightPipeline.LIGHT_COUNT` constant has been removed as it's not used internally.
* The `LightPipeline` previous created a global level temporary vec2 for calculations. This is now part of the class as the new `tempVec2` property.
The WebGL Graphics Pipeline has been removed. This pipeline wasn't used in v3.55, as all Graphics rendering is handled by the MultiTint pipeline, for better batching support. No Phaser Game Objects use the Graphics pipeline any longer, so to save space it has been removed and is no longer installed by the Pipeline Manager.
