jshint: add .jshintrc / .jshintignore files
* More commits to follow that further fine-tune the settings and fix
lint errors in the actual files.
* Quick how-to on how to use jshint from the command-line interface:
- Prerequisites: node and npm
http://nodejs.org/
http://npmjs.org/
- `$ npm install -g jshint`
https://github.com/jshint/node-jshint/
- Done!
All: `/mediawiki/core$ jshint .`
Dir: `/mediawiki/core$ jshint resources`
Dir: `/mediawiki/core$ jshint resources/jquery`
File(s): `/mediawiki/core$ jshint resources/startup.js resources/mediawiki/mediawiki.js`
Change-Id: Ia9297cb72c8faa7543ccfbdf48c7ee4e8af4ae17