Remove lodash.isarray (use native Array.isArray).

Other code was already depending on Object.keys() and
Array.prototype.filter(), which are also ES5 along with
Array.isArray().

lib/po.js

@@ -1,5 +1,4 @@
 var fs = require('fs');
-var isArray = require('lodash.isarray');
 
 function trim(string) {
     return string.replace(/^\s+|\s+$/g, '');
@@ -317,12 +316,12 @@ PO.Item.prototype.toString = function () {
     ['msgctxt', 'msgid', 'msgid_plural', 'msgstr'].forEach(function (keyword) {
         var text = self[keyword];
         if (text != null) {
-            if (isArray(text) && text.length > 1) {
+            if (Array.isArray(text) && text.length > 1) {
                 text.forEach(function (t, i) {
                     lines = lines.concat(mkObsolete + _process(keyword, t, i));
                 });
             } else {
-                text = isArray(text) ? text.join() : text;
+                text = Array.isArray(text) ? text.join() : text;
                 var processed = _process(keyword, text);
                 //handle \n in single-line texts (can not be handled in _escape)
                 for (var i = 1; i < processed.length - 1; i++) {

package.json

@@ -46,7 +46,5 @@
     "grunt-jscs": "~3.0.1",
     "grunt-mocha-cli": "~3.0.0"
   },
-  "dependencies": {
-    "lodash.isarray": "~2.4.1"
-  }
+  "dependencies": {}
 }