* `WebGLRenderer.setTextureZero` is a new method that activates texture zero and binds the given texture to it. Useful for fbo backed game objects.
* `WebGLRenderer.clearTextureZero` is a new method that clears the texture tha was bound to unit zero.
* `WebGLRenderer.textureZero` is a new property that holds the currently bound unit zero texture.
* The property `WebGLRenderer.currentActiveTextureUnit` has been renamed to `currentActiveTexture`.
* `WebGLRenderer.startActiveTexture` is a new read-only property contains the current starting active texture unit.
* `WebGLRenderer.maxTextures` is a new read-only property that contains the maximum number of texture units WebGL can use.
* `WebGLRenderer.textureIndexes` is a new read-only array that contains all of the available WebGL texture units.
* `WebGLRenderer.tempTextures` is a new read-only array that contains temporary WebGL textures.
* The `WebGLRenderer.currentTextures` property has been removed, as it's no longer used.
* `WebGLRenderer.currentTextures` has been removed, as it's no longer used internally.
* `WebGLRenderer.setBlankTexture` no longer has a `force` parameter, as it's set by default.
* `WebGLRenderer.setTextureSource` is a new method, used by pipelines and Game Objects, that will assign a texture unit to the given Texture Source.
* The `WebGLRenderer.setTexture2D` method has been updated to use the new texture unit assignment. It no longer takes the `textureUnit` or `flush` parameters and these have been removed from its method signature.
* The Texture Tint vertex and fragment shaders have been updated to support the `inTexId` float attribute and dynamic generation.
* The Texture Tint Pipeline has a new attribute, `inTexId` which is a `gl.FLOAT`.
* `TextureTintPipeline.bind` is a new method that sets the `uMainSampler` uniform.
* The `TextureTintPipeline.requireTextureBatch` method has been removed, as it's no longer required.
* The `TextureTintPipeline.pushBatch` method has been removed, as it's no longer required.
* The `TextureTintPipeline.maxQuads` property has been removed, as it's no longer required.
* The `TextureTintPipeline.batches` property has been removed, as it's no longer required.
* `TextureTintPipeline.flush` has been rewritten to support multi-textures.
* `TextureTintPipeline.flush` no longer creates a sub-array if the batch is full, but instead uses `bufferData` for speed.
* `TextureTintPipeline.currentUnit` is a new property that holds the most recently assigned texture unit. Treat as read-only.
