RabbitVPN http obfs demo

[itrump]

Hi Yicheng, Thanks for your work on the demo project.

  I have forked your RabbitVPN code, and find it great to learn how to develop a vpn with NEKit.

  Now pure shadowsocks network flow is detected by GFW, and obfs mode works well. 

 So, Would you please update some demo code of how to develop a http obfs feature on RabbitVPN project?

 Thank you in advance.