Added pskl.utils.Environment for detecting if Piskel is running in Node-Webkit.

src/js/utils/Environment.js

@@ -0,0 +1,25 @@
+/**
+ *  detection method from:
+ *  http://videlais.com/2014/08/23/lessons-learned-from-detecting-node-webkit/
+ */
+
+(function () {
+
+  var ns = $.namespace('pskl.utils');
+
+  ns.Environment = {
+    detectNodeWebkit : function () {
+      var isNode = (typeof process !== "undefined" && typeof require !== "undefined");
+      var isNodeWebkit = false;
+      if (isNode) {
+        try {
+          isNodeWebkit = (typeof require('nw.gui') !== "undefined");
+        } catch (e) {
+          isNodeWebkit = false;
+        }
+      }
+      return isNodeWebkit;
+    }
+  };
+
+})();

src/piskel-script-list.js

@@ -22,6 +22,7 @@
   "js/utils/FileUtils.js",
   "js/utils/FrameTransform.js",
   "js/utils/FrameUtils.js",
+  "js/utils/Environment.js",
   "js/utils/LayerUtils.js",
   "js/utils/ImageResizer.js",
   "js/utils/PixelUtils.js",