support NULL object as no timeout to event_add()
delete evBase from "struct CEvent"
rename Lib.Libevent/sample/test.k =>echoServer.k
rename "CEvent*" -> "Cevent*"
rename "CallBackArg" => "EventCallBackArg"
revise call sequence including parameters like libevent style
support event_del()
generate Event Object key to use as Map key
Merge pull request #397 from tosnoz/libevent_reviseAPI

Libevent revise api