optimise lodash usage; change contains function to includes for convenience

lib/6to5/generation/buffer.js

@@ -3,7 +3,7 @@
 module.exports = Buffer;
 
 var isBoolean = require("lodash/lang/isBoolean");
-var contains  = require("lodash/collection/contains");
+var includes  = require("lodash/collection/includes");
 var isNumber  = require("lodash/lang/isNumber");
 var util      = require("../util");
 
@@ -159,7 +159,7 @@ Buffer.prototype.isLast = function (cha, trimRight) {
   var last = buf[buf.length - 1];
 
   if (Array.isArray(cha)) {
-    return contains(cha, last);
+    return includes(cha, last);
   } else {
     return cha === last;
   }