- Update to 1.13.1:
* regression fix if `_fg=False` [#520](https://github.com/amoffat/sh/issues/520)
* minor Travis CI fixes [#492](https://github.com/amoffat/sh/pull/492)
* bugfix for boolean long options not respecting `_long_prefix` [#488](https://github.com/amoffat/sh/pull/488)
* fix deprecation warning on Python 3.6 regexes [#482](https://github.com/amoffat/sh/pull/482)
* `_pass_fds` and `_close_fds` special kwargs for controlling file descriptor inheritance in child.
* more efficiently closing inherited fds [#406](https://github.com/amoffat/sh/issues/406)
* bugfix where passing invalid dictionary to `_env` will cause a mysterious child 255 exit code. [#497](https://github.com/amoffat/sh/pull/497)
* bugfix where `_in` using 0 or `sys.stdin` wasn't behaving like a TTY, if it was in fact a TTY. [#514](https://github.com/amoffat/sh/issues/514)
* bugfix where `help(sh)` raised an exception [#455](https://github.com/amoffat/sh/issues/455)
* bugfix fixing broken interactive ssh tutorial from docs
* change to automatic tty merging into a single pty if `_tty_in=True` and `_tty_out=True`
* introducing `_unify_ttys`, default False, which allows explicit tty merging into single pty
* contrib command for `ssh` connections requiring passwords
* performance fix for polling output too fast when using `_iter` [#462](https://github.com/amoffat/sh/issues/462)
* execution contexts can now be used in python shell [#466](https://github.com/amoffat/sh/pull/466)
* bugfix `ErrorReturnCode` instances can now be pickled
* bugfix passing empty string or `None` for `_in` hanged [#427](https://github.com/amoffat/sh/pull/427)
* bugfix where passing a filename or file-like object to `_out` wasn't using os.dup2 [#449](https://github.com/amoffat/sh/issues/449)
* regression make `_fg` work with `_cwd` again [#330](https://github.com/amoffat/sh/issues/330)
* an invalid `_cwd` now raises a `ForkException` not an `OSError`.
* AIX support [#477](https://github.com/amoffat/sh/issues/477)
* added a `timeout=None` param to `RunningCommand.wait()` [#515](https://github.com/amoffat/sh/issues/515)
- Re-enable tests.
- Refresh no-coverage.patch, fix-test_general_signal.diff and
fix-test_signal_group.diff
- Add fix-sleep-path-in-test.patch to fix a test failure.
- Drop no longer required patches,
0001-Fix-tests-for-the-drop-the-unversion-python.patch,
always-use-fully-versioned-python-command-in-tests.patch and
pep-0538-test-fix.patch