[dwm] hg tip / upcoming 4.9

The current hg tip feels a little bit more like 4.7 again.

First of all DEFGEOM is a stayer, but I changed certain things
as follows:

The geometry indicator is only displayed in the bar, if there
are more than a single geometry.

Same applies to the layout indicator -- though only very few
people use dwm with tilev only.

setgeom and setlayout are togglable again, which means the
direct layout setting shortcuts are not part of the default
config anymore, instead I introduced:

Mod1-space for toggling between all layouts and

Mod1-Control-space for toggling between all geometries.

This change allowed me to introduce double mfact and setmfact()
again, which decreases/increases the master size.

The key bindings for this are

Mod1-h and Mod1-l again.

Kind regards,

-- 
 Anselm R. Garbe >< http://www.suckless.org/ >< GPG key: 0D73F361