v0.2.0

[Breaking Changes]

• WebGLRenderPass -> WebGLRenderer.
• WebGLRenderer: add beginRender() and endRender() methods. If you are using renderScene() method, they are already called internally.
• WebGLRenderer: rename renderer.gl to renderer.context.
• Refactor WebGLProperties to PropertyMap. The key value of webgl resource obtained from the object is changed to _gl{id}$.

[Other Changes]

• Material: add forceUpdateUniforms property.
• FileLoader: optimize progress event.
• WebGLRenderPass: export the init method to handle contextlost.
• WebGLRenderPass: add shaderCompileOptions.
• Examples: Add unrealbloom example.
• Remove long-deprecated code.
• GLTFLoader: Remove the unique processing of node names.