* Update licenses
* Update license for audio
* Update license for core/3d
* Update license for animation, assets, asset-manager, components, data
* update license for event, geometry, gfx
* update license for core modules
math, memop, pipeline, platform, primitive, renderer, scene-graph, utils, value-types
* Update license for core
* Update license for particle and particle-2d
* Update license for particle part2
* Update license for physics and physics-2d
* Update license for all modules in cocos
* Update license for exports
* Fix API doc language declaration
* remove asserts from addChild
* expose js._registeredClassIds & js._registeredClassNames (sync #3174)
To unload scripts dynamically.
Also revert part of changes from https://github.com/cocos-creator/engine/pull/3204/files#diff-cabe5229c3c6e31339220008e54fe853L421
* remove unused code (sync #3174)
* minor tweak (sync #3421)
* should not invoke component if destroy() called before node activating (sync #3430)
* node should removed and destroyed with scene (sync #3456#3483)
* fix WebGL detection on Android browsers (sync #3510)
* remove redundant right shift for bitwise operation (sync #3754)
* fix label blur when using dark font color (sync #3949)
* refine tooltip of Block Input Event (sync #4053)
* fix IE/Edge exception when output log/warn before engine initialization(sync #4447, #4500)
* sync class, attribute (#4689, #4712, #4781, #4712)
* fix loading unknown texture format (sync #4820)
* prefer toLowerCase to toLocaleLowerCase + sync #5114
* optimize bezier calculation (sync #5155)
* fix potential memory leak in scene-editor (sync #5643)
* fix _posDirty error of Mask on native platform (sync #6168)
* Event api translation
* Event manager API translation
* Macro cleanup and API doc improve
* Code cleanup and API translation in core/platform,
* Use macro.ENABLE_WEBGL_ANTIALIAS for initialization
* tweak
* Improve singleton ref in view
* Fix ci
* Export sys without default