Switch to using url scheme wrappers instead of duplicating each command we wrap. The 'hg svn url' command has been killed; the replacement is '.hg/hgrc'. More stuff related to its disappearance has been stripped, including two tests. HgChangeReceiver now takes a UUID argument, which it uses to ensure that remote repositories remain unchanged. This is a temporary solution, and I'm not entirely satisfied with how it's done either. Access to the UUID file has been isolated in a HgChangeReceiver property. Some more tests have been updated to use ui.pushbuffer()/popbuffer(), and to pass through the Mercurial API. Moved the arguments to wrappers.pull() to the UI configuration. Also, remove HgChangeReceiver.opts in favour of a 'usebranchnames' instance & configuration variable. The name is taken from the ConvertExtension.