Relocate 3rd-part packages; Add go_get_helper.go for auto fetch 3rd-part packages when get gopush

Relocated 3rd-part packages:

code.google.com/p/go.net/websocket -> github.com/gdier/go-net-websocket
launchpad.net/gozk/zookeeper -> github.com/gdier/gozk-zookeeper