Improve createReducer

This change allows us to write reducers which depend on additional data as described here: reduxjs/redux#749 (comment)

src/utils/index.js

@@ -11,10 +11,10 @@ export function createConstants (...constants) {
 }
 
 export function createReducer (initialState, fnMap) {
-  return (state = initialState, { type, payload }) => {
+  return (state = initialState, { type, payload }, ...rest) => {
     const handler = fnMap[type];
 
-    return handler ? handler(state, payload) : state;
+    return handler ? handler(state, payload, ...rest) : state;
   };
 }