patch applied (cabal): Add markdown version of user guide

Sun Apr 11 09:10:12 PDT 2010 Duncan Coutts * Add markdown version of user guide Plan is to switch over from docbook xml. A ./doc/Cabal.markdown View patch online: http://darcs.haskell.org/cgi-bin/darcsweb.cgi?r=cabal;a=darcs_commitdiff;h=2...