Add man page support

[DataDrake]

It's inevitable that someone will want to see us generating man pages. This should be implemented as a simple text\template which dumps out a man page in the default locale. These man pages should mirror how git does them: one man page for the whole utility, referencing individual man pages for each non-hidden subcommand (e.g. git-commit).

[DataDrake]

Eh, text/template is more effort than it is worth for generating man-pages.