Update dependencies to enable Greenkeeper 🌴 (#20)

* chore(package): update dependencies

https://greenkeeper.io/

* docs(readme): add Greenkeeper badge 

https://greenkeeper.io/

* Remove badge

Author: greenkeeper[bot]

package.json

@@ -22,7 +22,7 @@
   "dependencies": {
     "@types/concat-stream": "^1.6.0",
     "@types/node": "^7.0.31",
-    "caseless": "~0.11.0",
+    "caseless": "~0.12.0",
     "concat-stream": "^1.4.6",
     "http-response-object": "^2.0.3",
     "parse-cache-control": "^1.0.1"