WinHugs, options dialog Haskell 98 mode

Hi, This patch implements the first page of the options dialog, including overlapping instances, here documents and haskell 98 mode. This does allow changing between haskell98 and not at runtime, but I have marked it with the warning "requires restart". This is not entirely true... If you load a non-haskell 98 doc with +98, it fails. If you then go to options and set -98, then either :l or :r, it succeeds. If you then go to options and flip back to +98, :r succeeds (wrongly), but :l fails. Thanks Neil