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.

--- a/tests/test_diff.py
+++ b/tests/test_diff.py
@@ -32,9 +32,9 @@ class DiffTests(test_util.TestBase):
                             ('alpha', 'alpha', 'alpha\n\nadded line\n'),
                             ])
         u = ui.ui()
-        wrappers.diff(lambda x,y,z: None,
-                         u, self.repo, svn=True)
-        self.assertEqual(u.stream.getvalue(), expected_diff_output)
+        u.pushbuffer()
+        wrappers.diff(lambda x,y,z: None, u, self.repo, svn=True)
+        self.assertEqual(u.popbuffer(), expected_diff_output)
 
 
 def suite():