remove unused variables

lib/6to5/transformation/transformers/_member-expression-literals.js

@@ -1,6 +1,6 @@
 var t = require("../../types");
 
-exports.MemberExpression = function (node, parent) {
+exports.MemberExpression = function (node) {
   var prop = node.property;
   if (node.computed && t.isLiteral(prop) && t.isValidIdentifier(prop.value)) {
     // computed literal that is a valid identifier

lib/6to5/transformation/transformers/_property-literals.js

@@ -1,6 +1,5 @@
 var esutils = require("esutils");
 var t       = require("../../types");
-var _       = require("lodash");
 
 exports.Property = function (node) {
   var key = node.key;