Add: shadowsocks_sysconf off/auto/global mode
Add: shadowsocksX switch Auto mode and Global mode
Add: shadowsocks_sysconf -v for detecting current version
Add: detect shadowsocks_sysconf version on startup
Update: redesign selection menu & green status bar icon for global mode.
Add: menu_icon_global.png & fix checkmark when proxy closed
remove unused comments; remember running mode when switched off, remove alert which sucks
close #39
update submodule url
support qrcode generation on OS X
disable qrcode menu when using public server
Merge branch 'master' of https://github.com/shadowsocks/shadowsocks-iOS