Add test_pull_named_remote (includes renaming)
Add failing tests for issue #30

Zero-content pull/fetch after push triggers a notes commit on
fast-import, which git applies successfully, but complains on stderr.

error: refs/notes/hg-84b3865b750a567acb16929c21e14c4a45a5639b does not point to a valid object

New tests:

* test_simple_push_updates_notes
  checks for automatic update after push followed by zero-content
  pull/fetch

* test_simple_push_updates_notes_after_contentful_pull
  checks for eventual update after a fetch/pull that provides content on
  a non-notes ref
Commit notes only when there is at least one non-notes commit (fixes #30)

Git is rejecting commits to refs/notes/hg-* when there are no other
commits in the fast-imports stream. I can't tell if this is intended
behavior (why would it be?) but deferring application of the notes works
around the problem.

Fixes test_simple_push_updates_notes_after_contentful_pull.

Leaving xfail test_simple_push_updates_notes to track when we can apply
notes more eagerly without messy stderr.
Merge pull request #32 from jedbrown/notes-in-empty-fetch

Notes in empty fetch (issue #30)
remotes can be renamed without tinkering with .git/refs/hg/remote-name, closes #14

Although .git/refs/hg/old-remote-name is not renamed or deleted
automatically, it is not harmful and the user can delete it at any time,
thus

    git remote rename old-remote-name new-remote-name

behaves acceptably with no further user interaction. Update
test_pull_named_remote to reflect this.
Move author name tests to separate file
Add more author name tests

Four are xfails, see issue #22. Also change existing tests to
test that whitespace in usernames cause no problems.
authorname: handle <email@example.com> correctly
Travis: also run tests against hg 1.8.4 and 1,6.4
Rearrange README.rst, display Travis status
Do not test old hg versions with new python
Add hg 2.5 to travis tests
Test what happens when a file is removed or replace by a dir

Right now, replacing a file by a dir causes an xfail, see
issue #36.
Disable Travis tests against hg 1.8.x and older for now.

There are some problems with them, see issue #20. We may
want to add support for these old hg versions in the future,
but for now, they are not supported.
Change setup.py to require at least Mercurial 1.9.1

See issue #20
sanitize_author: more complete regex, ref #22
test_author_abuse_quotes: provide a possible resolution
Add tests for replacing files and dirs with symlinks and vice versa

This uncovered yet another variant of issue #36: Replacing a symlink
by a directory also does not work correctly.
sanitize_author: ensure that author name is stripped of whitespace
Add failing test_fetch_after_bad_push_updates_origin_master