In general I don't like adding generated content to the repository,
but I also want to make it possible to clone the repository and
'cabal install'. THe current system with Setup.hs calling
MakeManPage.hs is too fragile.
* Markdown syntax description from README now goes in pandoc_markdown.5.
* Refactored man page construction functions, putting more of
the work in MakeManPages.hs.