Documentation update
- make it clear that you have to have an existing repo to clone
- don't try to put the same key in different directories
- explain the .mercurial-server file.
Document: mercurial-server
Title: mercurial-server manual
Section: Programming
Format: HTML
Index: /usr/share/doc/mercurial-server/html/index.html
Files: /usr/share/doc/mercurial-server/html/*.html