more EWMH support: all types, states and actions

- trivial support for _NET_WM_STATE_STICKY (unused)
- trivial support for _NET_WM_STATE_SKIP_TASKBAR (unused)
- trivial support for _NET_WM_STATE_SKIP_PAGER (unused)
- support for _NET_WM_STATE_DEMANDS_ATTENTION
- support for _NET_WM_STATE_FOCUSED

- trivial support for _NET_WM_ACTION_STICK

- trivial support for _NET_DESKTOP_LAYOUT (unused)
- trivial support for _NET_HANDLED_ICONS (unused)