MUMUP-1361 : Try out ng session storage

This utilizes [ngStorage](https://github.com/gsklee/ngStorage)
+ Saves marketplace information to the [sessionStorage](http://www.w3schools.com/html/html5_webstorage.asp).
+ This will make it so no server hit will happen, even if they go to `/portal` and back :smile: 
+ Minor cleanup to button for already on home scenario 

![image](https://cloud.githubusercontent.com/assets/3534544/5147014/b7215fbc-7177-11e4-8e1f-4106368a1989.png)