new module NoBorders to let a given layout have windows without borders.

This is designed for layouts like full and tabbed, where the red square
around the screen actually conveys no information (except for weird windows
that use the shape extension or something, so that more than one window is
actually visible).  Save some real estate at no cost.

MetaModule.hs

@@ -23,6 +23,7 @@ import XMonadContrib.HintedTile ()
 import XMonadContrib.LayoutHints ()
 import XMonadContrib.Mosaic ()
 import XMonadContrib.NamedWindows ()
+import XMonadContrib.NoBorders ()
 import XMonadContrib.RotView ()
 import XMonadContrib.SimpleDate ()
 import XMonadContrib.Spiral ()