参考资料：
https://linux.cn/article-3487-2.html
https://jingyan.baidu.com/article/d2b1d1027ec8d85c7e37d492.html
https://jingyan.baidu.com/article/95c9d20dae5342ec4e75613b.html
http://www.oschina.net/p/cairodock/
Ubuntu 主题库：
http://ppa.launchpad.net/noobslab/themes/ubuntu/pool/main/
