Simplified Setup.hs.

It no longer builds and installs man pages.

All it does is hook the hsb preprocessor.

This should make the build process more robust over Cabal API
changes.  We'll add a Makefile to generate man pages.
Revised tests directory.

Renamed some tests, introducing subsidiary directories
for fb2, docx, epub.

Cleaned up tests in cabal file.

Combined dokuwiki-writer and dokuwiki_inline_formatting tests.