add Bower and update related to Safari Web Content Guide

add bower.json for Bower package Manager

add size : 

* 60x60
* 76x76
* 120x120
* 152x152

related to Safari Web Content Guide : https://developer.apple.com/library/ios/documentation/AppleApplications/Reference/SafariWebContent/ConfiguringWebApplications/ConfiguringWebApplications.html