First round of updates
First round of updates

Changes:
 - Remove hoogle 4->5 prelude
 - Change haskell.org/hoogle to hoogle.haskell.org where relevant
 - Correct "The Source Code" section to refer to github
 - Have "Neil Mitchell" link to ndmitchell.com rather than defunct
   community.haskell.org page

ndmitchell/hoogle,ndmitchell/hoogle,ndmitchell/hoogle