[dwm] way towards 5.0

Here are the most recent changes I did to the codebase today
(most stuff towards 5.0 is done now).

- DEFGEOM is replaced by a function updategeom(), and a function
pointer updategeom in each layout definition

- removed Client->{fx,fy,fw,fh}

- removed reapply()

- removed tileh*, counttiled(), etc stuff

- moved all tile-related stuff to tile.c, which is included in
config.h. tile.c contains tile(), setmfact(), zoom() and a new
updatetilegeom() function. tile.c also includes the definition
of mfact, m{x,y,w,h} and t{x,y,w,h}

- renamed nexttiled() into nextunfloating()

- removed monocle (temporarily until I write this monocle
meta-layout which will be toggled when Mod1-m is pressed)

- renamed setlayout() into togglelayout()

This means, that if tile.c isn't included in config.def.h, dwm
can be used as a floating wm, which provides all core
functionality and our tagging approach.

This also means, that for people like me, who use a multihead
setup sometimes, can include a hacked version of tile.c which
provides a different updatetilegeom() and maybe a slightly
different tile() algorithm itself.

Conceptually this is now rather clean, because we also get rid
of Bool dozoom/domfact due to the code organization, that all
tile-related functions are in tile.c now and can check if
lt->arrange == tile, and then perform the necessary function or
decline.

The Layout interface hasn't changed much in this regard.

I plan to add some more convenience toggles to config.def.h to
influence the default updategeom() function a little bit for the
bar geometry/position.

Do people prefer having a fine-grain bar positioning setup or is
it more preferred to have a bar setup in the sense "top or
bottom"? I still believe the latter idea is nicer, if someone
wants to use dzen, patch updategeom on you own.

Let me know how welcome do you feel about those changes. Bug
reports are also welcome.

Kind regards,

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