Import help files from Hextrapolate (REnamer, 3b343f9)

The help files in REnamer predate Walrus, so move the old help files out of the way and import the Walrus-based help documents from Hextrapolate. These will serve as a basis for integrating Walrus into the help documentation generation for REnamer.

Signed-off-by: Greg Hurrell <greg@hurrell.net>