Data center visualization

Changes:
* new view ``DataCenterView``,
* refactored angular app structure,
* added new type of device (accessory).

describe what does mean x and y. 
/*
 * Some description
 * @param {integer} y: message to display
 * @param {boolean} x: error or success color for message container
 */

and comment rest of code


http://usejsdoc.org/tags-param.html
https://developers.google.com/closure/compiler/docs/js-for-compiler