add tapable

Author: nkumar-topcoder

package.json

@@ -77,6 +77,7 @@
     "xml2js": "0.4.17",
     "zepto": "1.0.1",
     "estraverse": "4.1.0",
-    "bluebird": "2.9.2"
+    "bluebird": "2.9.2",
+    "tapable": "1.0.0"
   }
 }