Add range filter

This is a very easy way to create loops in the template.

Let's say you want to make a <ul> with 5 <li> elements. It is as simple as this:

````
<ul>
  <li ng-repeat="item in range(5)">Item</li>
</ul>
````

This filter is very flexible and allows setting a step, and start number as well. I added some unit tests as well as adding it to the build configurations.