Merge branch 'fc/remote-hg'

* fc/remote-hg: (50 commits)
  remote-hg: add support for --force
  remote-hg: add support for --dry-run
  remote-hg: check if a fetch is needed
  remote-hg: trivial cleanup
  remote-helpers: improve marks usage
  remote-hg: add check_push() helper
  remote-hg: add setup_big_push() helper
  remote-hg: remove files before modifications
  remote-hg: improve lightweight tag author
  remote-hg: use remote 'default' not local one
  remote-hg: improve branch listing
  remote-hg: simplify branch_tip()
  remote-hg: check diverged bookmarks
  remote-hg: pass around revision refs
  remote-hg: implement custom checkheads()
  remote-hg: implement custom push()
  remote-hg: only update necessary revisions
  remote-hg: force remote bookmark push selectively
  remote-hg: reorganize bookmark handling
  remote-hg: add test for failed double push
  ...

Author: gitster

contrib/remote-helpers/git-remote-bzr

@@ -116,7 +116,10 @@ class Marks:
         self.last_mark = mark
 
     def get_tip(self, branch):
-        return self.tips.get(branch, None)
+        try:
+            return str(self.tips[branch])
+        except KeyError:
+            return None
 
     def set_tip(self, branch, tip):
         self.tips[branch] = tip