Tags: ltq/cow

Merge branch 'develop', version 0.7.6

Merge branch 'develop', version 0.7.5

Merge branch 'develop', version 0.7.4

Merge branch 'develop', version 0.7.3

Avoid opening too many sockets, support authenticate multiple users.

Fix parent proxy fallback bug.

Multiple SOCKS/HTTP proxy support, internal IP direct only.

Support more shadowsocks encryption methods.

HTTP parent proxy basic auth, bug fixes.

Performance optimization.