Fix command parser: resizing tiling windows

Long description:

i3 would accept an invalid resize command like 'resize shrink width 10
px or' without specifying the ppt value, and then crash. This patch
fixes the parser specification.

To apply this patch, use:
curl http://cr.i3wm.org/patch/259/raw.patch | git am

@@ -209,11 +209,11 @@ state RESIZE_TILING:

       -> call cmd_resize($way, $direction, $resize_px, "10")

 state RESIZE_TILING_OR:

-  'ppt'

-      ->

   resize_ppt = word

-      ->

-  end

+      -> RESIZE_TILING_FINAL

+

+state RESIZE_TILING_FINAL:

+  'ppt', end

       -> call cmd_resize($way, $direction, $resize_px, $resize_ppt)

 # rename workspace <name> to <name>