add more features

[MrGandotra]

There is no error but would like to ask for some features in final one ui 2.0 update. 

1.) Double tap to onoff screen from home screen. 2.) Volume slider in notification panel just like brightness slider. 

3.) Iris scanner protection as applock

I hope samsung software development team give consideration to this request. 

- a long term samsung fan.

[LkyVivaan]

1 and 3rd feature plz add