Added goport.events.EventEmitter class and its test files.

goport.events.EventEmitter class is a simple port of node's
events.EventEmitter clas.
Rename
go fmt
Added EventEmitter.InitEventEmitter().
Once, RemoveListener, RemoveAllListener in events.EventEmitter
No raw is needed in eventHandler
Make lock private
Add limit of RemoveListener
With more modifications.
Change eventemitter from parallelized to single threaded.
solve dead lock