feat(utils): getOutgoers function

src/index.js

@@ -2,11 +2,13 @@ import ReactGraph from './ReactGraph';
 import {
   isNode as _isNode ,
   isEdge as _isEdge,
-  removeElements as _removeElements
+  removeElements as _removeElements,
+  getOutgoers as _getOutgoers
 } from './graph-utils';
 
 export const isNode = _isNode;
 export const isEdge = _isEdge;
 export const removeElements = _removeElements;
+export const getOutgoers = _getOutgoers;
 
 export default ReactGraph;