fix $log and Engine.log to Actor#log
Merge pull request #227 from sonots/fix_v11_log

[v11] fix $log and Engine.log to Actor#log
SocketActor::CallbackListener#on_connection should not close socket
Merge branch 'v11' into v11-match-copy-syntax
removed FilterOutput
removed EventRouter::Offset
fixed specs
changed <worker> tag to <server> tag