Rename jshint_conf.js to .jshintrc

By doing this sublime text and webstorm will start reporting jshint errors inside the editor.

For Sublime Text:
- Install package SublimeLinter
- Install package SublimeLinter - jshint
- From Terminal `npm install -g jshint`

For WebStorm
- Preference -> JSHint
- Make sure `Enable` and `Use config files` are selected
Most IDE follow this rule:
> start looking for this file in the same directory as the file that's being linted. If not found, it will move one level up the directory tree all the way up to the filesystem root.

Putting `.jshintrc` on the root means that it applies also for `Gruntfile.js`, `grunt-configs` and other files that are node scripts, so they have different rules.
I'll have a look at all files in the repository and see if there's a better approach.