Same as node Events with support for handler context
This is a "fork" of node's Events module with support for specifying a context for the handler
Everything is the same as Events except:
If the context is not specified,
this (the emitter) will be used as the context.
var Emitter =x =;var context = foo: 'bar' ;x;x;// true - There are listeners for `baz`// 'bar'