Remove unused express devdep

Author: ndhoule

package.json

@@ -4,7 +4,6 @@
   "devDependencies": {
     "duo": "^0.12.3",
     "duo-test": "^0.4.1",
-    "express": "~3.1.0",
     "mocha": "^1.20.1",
     "phantomjs": "^1.9.17"
   }