建议加入对ipv6的支持

[bestmikecat]

原版的Kitsunebi是支持打开ipv6网站的，希望能加入这一功能，另外在关闭代理时程序会闪退，希望改进，并更新至xray1.40，谢谢。

[rurirei]

1. ipv6 will make a test one
2. bugs of android app put it off (wait for new one implemented)
3. xray-core upstream waiting for more commit

[rurirei]

ipv6 see latest release.

[bestmikecat]

ipv6 works fine now, it's a good client software, more features can be added, keep optimizing it, thanks! @rurirei