Make share/man/man1 manpages get built again
Addresses https://github.com/fish-shell/fish-shell/issues/491
Make the Makefile mv man pages instead of cp them from help_doc, because help_doc is about to be deleted
Change build_documentation to take its paths as arguments, and the Makefile.in to pass them
Teach Xcode how to pass arguments to build_documentation.sh
Teach the Xcode project how to install the man pages