awful.client.tiled: Ignore fullscreen (etc) clients (FS#1106)

I am looking forward to the bug reports requesting awful.client.floating.set(c,
true) to also automatically un-fullscreen the client...

Signed-off-by: Uli Schlachter <psychon@znc.in>

lib/awful/client.lua.in

@@ -220,7 +220,10 @@ function client.tiled(screen)
     local tclients = {}
     -- Remove floating clients
     for k, c in pairs(clients) do
-        if not client.floating.get(c) then
+        if not client.floating.get(c)
+            and not c.fullscreen
+            and not c.maximized_vertical
+            and not c.maximized_horizontal then
             table.insert(tclients, c)
         end
     end