chore(package): update browserify to version 15.1.0

Closes #14

Author: greenkeeper[bot]

package.json

@@ -26,7 +26,7 @@
   "author": "IndigoUnited <[email protected]> (http://indigounited.com)",
   "license": "MIT",
   "devDependencies": {
-    "browserify": "^14.0.0",
+    "browserify": "^15.1.0",
     "expect.js": "^0.3.1",
     "mocha": "^3.0.2"
   },