[dwm] incremental stack patch

another one from stupid patchs (tm). i wrote this one as an exercise,
curiosity...
It changes the behaviour of the stack and now it is incremental: you
define in config.h INCSTACK 0.75 and the second stack window height
will be the 75% of the first one, the third window the 75% of the
second one, etc.
It complicates the source (it was so clean!...) and adds the math.h
dependency. OTOH, it doesn't really mean a great improvement: if
INCSTACK is near to 1 you don't feel any difference, and if it is near
to 0 you can't have too many clients in the stack.
I plan to release a mousemode patch against dwm 3.0, but the
incremental stack patch will be unmaintained. I just wanted to send it
to the list because somebody could think it would be useful.

cu at #dwm

-- 
- yiyus || JGL .