Implement Grunt

I implemented a Grunt task for watching changes on the Sass and Javascript files to process them.
The script compiles the Sass files, exactly like the compass gem was doing, and concatenates and minifies the Javascript files into a single script.

To use Grunt you'll need Node.js installed. You can get Node on the [website](http://nodejs.org/) or installing via ```brew install node```

After installing Node you'll need to install ```grunt-cli``` npm package: ```npm install -g grunt-cli```.
You can also follow along the [Getting Started guide](http://gruntjs.com/getting-started)

Then after setting things up, run: ```npm install``` on the folder of the project. This will download the grunt dependencies. And then run ```grunt watch``` and you're good to go! Phew!

Grunt will watch for changes on the Sass and Javascript files and run the process.

This will deprecate the Foreman.

@mikaelcarrara can you do some testing and see if the stylesheet is compiling right and the javascript is not messed up? I did some checking, but I guess you know better.

If anyone wants to test this and needs help, ask me for support.

Hugs