Add a multi-repository server
This merges a bunch of the ideas for a multi-repository CGI script and
simplifies things a bit.
It uses PATH_INFO so it generally wants paths of the form:
http://host/hg.cgi/virtualpath
This gets mapped via a simple config file to the real path. All info
about the repo is read from the repo's hgrc.
#header#
# HG changeset patch
# User #author#
# Date #date|date#
# Node ID #node#
#parent#
#desc#
#diff#