[wmii] Increment handling

Hello all,

sqweek complained on IRC about wmii's increment handling, so I sat down and implemented a patch for that. Instead making a frame 2*border + client-rect large, the patch just gives the frame the size it should take in the column and centers the client-rect inside the frame. Here it goes:

        http://www.ueberl33t.net/tmp/increment_handling_improved.patch

Unfortunately, it breaks the increment handling relaxation algorithm, which should be reviewed.

Greetings,
Denis