General chores on package

Hi Patrick :smiley: 

Here's an overview of the changes included in this pull request:
* Moved to version number 0.5.8
* Fixed bower.json of distribution package so that the `main` path is now a valid path
    * Fixes issue that grunt-wiredep couldn't inject angular-momentum-scroll
* Bower package version contains now build timestamp
* Modified build process so that the minified file holds now proper license informations of angular-momentum-scroll and the used iScroll library
* Wrapped scrollable.js into an IIFE to avoid code leaking
* Source map gets now included into the distribution package
* Updated NPM and Bower dependencies
* Updated Karma test suite
* Build uses now ng-annotate which makes dependency injection less error prone

Build timestamp can be useful if you want to publish several pre-releases or daily builds of that package e.g.:
* 0.5.8-20140720
* 0.5.8-20140722
* 0.5.8 (final release)

Generally it would be a good idea to not include the iScroll library directly into the `scrollable.js` so that the user can choose on it's own which version he wants to take.

Note: If there'll be a merge conflict with my other pull-request I fix it.