func (p *Emitter) On(event string, handler EventHandler) {
	p.emitter.On(event, handler)
}
On register a function. Note that the pointer to the function need to be
the same to be removed with Off
package emitter
import (
	"github.com/chuckpreslar/emission"
)
type EventHandler func(interface{})
func NewEmitter() Emitter {
	return Emitter{
		emitter: emission.NewEmitter(),
	}
}
type Emitter struct {
	emitter *emission.Emitter
}
func (p *Emitter) Emit(event string, data interface{}) {
	p.emitter.Emit(event, data)
}