Feature request: add 'count' to instances

[markocelan]

Problem
I want to plan costs for clusters of machines, which means there are pools of servers that are basically the same - down to it's name. For me it is not viable to add them one by one, and even if I did that programmatically, gcosts output would be only marginally useful.

It would be great if there would be a 'count' (or similar) option to tell gcosts that you want it to account for many of these instances.

Maybe it's useful in some other context, other than instances, too.