Adding simple Grunt configuration to perform JShint linting task.

Hi,

I added a simple task runner with Grunt, just for JShinting for now, we can extend it with more tasks later.

The goals is to specify JShint setting for all contributors, since http://www.jshint.com/docs/config/ has a bunch of them.

Run ```npm install```

And then available tasks:
```javascript
grunt 
grunt jshint:server
grunt jshint:client
```

Default setting a pretty strict such as ```onevar``` (http://www.jshint.com/docs/options/#onevar) and it sometimes hard to follow,  but we will have much stable builds.

Also i added ```.jshintrc``` with the default JShint settings ( node.js based), it's helpful if you work in IDE, so those setting catching up automatically. ```.jshintignore``` could be used for the same default purpose.

If we will go with this approach I can add ```watch``` tasks for autolinting when code is changed.

Anyway there are many useful things which we can add with Grunt.

Please take a look and let me know what do you think.