Update to improve history api error and bad request handling

Author: jackycute

lib/response.js

@@ -33,6 +33,9 @@ var response = {
     errorNotFound: function (res) {
         responseError(res, "404", "Not Found", "oops.");
     },
+    errorBadRequest: function (res) {
+        responseError(res, "400", "Bad Request", "something not right.");
+    },
     errorInternalError: function (res) {
         responseError(res, "500", "Internal Error", "wtf.");
     },