util: use 'auditor' as consistent name for path auditors

util: add optional path auditor argument to canonpath The canonpath function will default to creating its own path auditor, but in some cases it will be useful to use a specialized auditor, e.g., one that wont abort if a path lies within a subrepository.

mail/hgweb: support service names for ports (issue2350) This adds util.getport(port) which tries to parse port as an int, and failing that, looks it up using socket.getservbyname(). Thus, the following will work: [smtp] port = submission [web] port = http This does not apply to ports in URLs used in clone, pull, etc.