Merge branch 'master' of github.com:XX-net/XX-Net

release 2.8.9

release 2.8.8

fix bug: can't keep alive for ssl link, release 2.8.7

avoid network fail confuse user when setting appid

fix bug: check appid not work for old GoAgent deployed appid, add sto…

…p check all exist ip, release 2.8.5

release 2.8.4

check ipv6 before enable it

release new version

new version release