Group/ungroup button in deco

[Maciej Pilichowski]

I am starting mini-threads, because honestly I am lost in all-in-one.

So -- simple questions, do we agree to add such (two) buttons to the 
deco, and make them visible by default?

1. group -- yes
2. ungroup -- (after rethinking) yes

I am not talking about changing the behaviour of grouping/ungroupping, 
just another way to trigger it, that's all.

Cheers,