[RP] some new commands

[Shawn Betts]

Hi guys,

So I messed up and committed some changes to the 1.2.0 branch (I just
made a 1.3.0 branch). I thought I'd mention them:

gnew, gnext and gprev

gnew creates a new window group.

gnext and gprev move between them.

so you more or less can do workspaces. You just need to save and
restore the frame layout when you switch groups.

But this allows you to switch to a different group and still see
windows from different groups in other frames.

Shawn