updated pngjs, old version produced uncatchable errors

package.json

@@ -16,13 +16,13 @@
   },
   "dependencies": {
     "coffee-script": "~ 1.7.1",
-    "jspack": "~ 0.0.3",
     "coffeescript-module": "~ 0.2.1",
-    "parse-engine-data": "~ 0.1",
-    "pngjs": "~ 0.4.0",
-    "rsvp": "~ 3.0.6",
+    "iconv-lite": "~ 0.4.4",
+    "jspack": "~ 0.0.3",
     "lodash": "~ 2.4",
-    "iconv-lite": "~ 0.4.4"
+    "parse-engine-data": "~ 0.1",
+    "pngjs": "^3.0.0",
+    "rsvp": "~ 3.0.6"
   },
   "scripts": {
     "test": "mocha test",