UGUI表情系统解决方案

参考链接：

https://blog.uwa4d.com/archives/Sparkle_UGUI.html

http://tech.seasungame.com/blog/index.php/2017/08/30/uguibiaoqingxitongjiejuefangan/

https://github.com/zouchunyi/EmojiText

http://blog.csdn.net/column/details/13021.html

https://github.com/coding2233/TextInlineSprite