CGI compatibility fix for
d74fc8dec2b4.
doc: add repo/ to .hgignore and .hgtags
These names were disappearing in the asciidoc output and no form of
escaping seems to help. Let's just add repo/ to make it explicit that
they're in the repository root.
hgweb: make web.name default to repo basename
Providing the full path to the repository by default
could be considered a security risk.