Merge branch 'fc/remote-hg' (early part)

* 'fc/remote-hg' (early part):
  remote-hg: update bookmarks when pulling
  remote-hg: don't push fake 'master' bookmark
  remote-hg: disable forced push by default
  remote-hg: fix new branch creation
  remote-hg: add new get_config_bool() helper
  remote-hg: enable track-branches in hg-git mode
  remote-hg: get rid of unused exception checks
  remote-hg: trivial cleanups