[xmonad] darcs patch: Add straightforward HiddenWS to WSType (and 1 more)

Hi, these two patches should be unproblematic, as they only add additional features. Please apply. Thanks, Joachim Mon Oct 6 23:05:48 CEST 2008 Joachim Breitner * Add straightforward HiddenWS to WSType With NonEmptyWS and HiddenNonEmptyWS present, HiddenWS is obviously missing. Mon Oct 6 23:10:27 CEST 2008 Joachim Breitner * Implement HiddenNonEmptyWS with HiddenWS and NonEmptyWS (Just to reduce code duplication)