tools: update ESLint to v3.8.0

Update ESLint to v3.8.0.

* Installed with `npm install --production` to avoid installing
  unnecessary dev files
* Used `dmn -f clean` to further eliminate unneeded files

PR-URL: https://github.com/nodejs/node/pull/9112
Reviewed-By: Teddy Katz <teddy.katz@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Roman Reiss <me@silverwind.io>

tools/eslint/node_modules/string_decoder/package.json

@@ -16,7 +16,6 @@
   "_from": "string_decoder@>=0.10.0 <0.11.0",
   "_id": "string_decoder@0.10.31",
   "_inCache": true,
-  "_installable": true,
   "_location": "/string_decoder",
   "_npmUser": {
     "name": "rvagg",