Sort out Mercurial push pull commands to operate like other DVCses.

src/pmr2/wfctrl/cmd.py

@@ -114,18 +114,24 @@ def pull(self, workspace, username=None, password=None, **kw):
         # XXX assuming repo is clean
         args = self._args(workspace, 'pull', target)
         output = self.execute(*args)
-        print("mercurial pull:")
-        print(output)
-        return output
+        return_code = 0
+        if output[1]:
+            return_code = 1
+
+        return '\n'.join(output[0]).encode(), output[1], return_code
 
     def push(self, workspace, username=None, password=None, **kw):
         # XXX origin may be undefined
         push_target = self.get_remote(workspace,
                                       username=username, password=password)
         args = self._args(workspace, 'push', push_target)
         output = self.execute(*args)
-        print("mercurial push:")
-        print(output)
+        if len(output) == 2:
+            return_code = 0
+            if output[1]:
+                return_code = 1
+            return '\n'.join(output[0]).encode(), output[1], return_code
+
         return output
 
     def reset_to_remote(self, workspace, branch=None):