place-window-interactively: ignore only ButtonRelease events

emacs for example, maps immediately if we ignore any event...
Mimic CTWM interactive placement features

When placement-mode is set to 'interactively, during the 3x3 grid
move:
- clicking Button2 and dragging the outline will give
  the window its current position but allow the sides to be resized;
- clicking Button3 will give the window its current position but
  attempt to make it long enough to touch the bottom the screen;
- releasing any other button still position the window at the current
  position, as before.

Thanks to CTWM project for its documentation.
add tab support for tiling
rename tab-group-windows-index to tab-group-windows
enable shade-hover and auto-raise in SawfishConfig, utilize them in tabbing
tweak default compton settings
fix wrong input-focus fom enter-* focus modes in tabbing
tweak StyleTab settings and update according previous commit
disable raise-windows-on-focus in tabbing if not set via SawfishConfig
major rework of sawfish.wm.ext.cabinet
update german translation
add cabinet-missing.png / sawfishimagedir to Makedefs.in
cabinet: improve improve move  window to next/prev workspace,
dynamic splitline length (cabinet width)
ensure cabinet height does not exceed screen boundaries
update sawfish.spec
bump version to 1.10.99 (Carrera Rapida)
update autotools
add pancake, lxpanel, Sawfishpager to cabinet ignore list
update Elberg-tabbed and gradient-tabbed for recent changes
Revert "update Elberg-tabbed and gradient-tabbed for recent changes"

This reverts commit fc6934fa871134dfaccd1094c0efc7a04c369ba7.