UI系列 19：样式主题
参考链接：
- https://juejin.im/entry/5a1c0964f265da43305e321d#comment
- https://github.com/fengjundev/Android-Skin-Loader
- https://blog.csdn.net/mathcompfrac/article/details/77984735
- https://blog.csdn.net/kongbaidepao/article/details/52106866
- https://blog.csdn.net/hqiong208/article/details/50295647
