Refs #4900. Updated async to IE10 compatible version.

package.json

@@ -23,7 +23,7 @@
   ],
   "dependencies": {
     "sift": "*",
-    "async": "*"
+	"async":"git+https://github.com/louischatriot/async"
   },
   "devDependencies": {
     "mocha": "*",