Implement _NET_WM_STATE_STICKY, bound to CM-s by default; allows any

client to 'stick' to all desktops (ewmh speak) or groups - this
currently has the same affect as setting a client's group to 'nogroup',
with the exception that the client can also be in a group, so when
un-sticking, the client will go back to its original group/desktop.

cwm.1

@@ -14,7 +14,7 @@
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: December 16 2013 $
+.Dd $Mdocdate$
 .Dt CWM 1
 .Os
 .Sh NAME
@@ -90,6 +90,8 @@ Cycle through active groups.
 Reverse cycle through active groups.
 .It Ic CMS-f
 Toggle freezing geometry of current window.
+.It Ic CM-s
+Toggle stickiness of current window.
 .It Ic CM-f
 Toggle full-screen mode of current window.
 .It Ic CM-m