Performance

--------------------------

* Upgrade Dulwich to 0.17.3 to support PyPy older than 5.6:
see https://github.com/jelmer/dulwich/issues/509
* Fix ResourceWarning warnings: close explicitly files and sockets.
* scripts: replace Mercurial commands with Git commands.
* Upgrade requirements:

- dulwich: 0.17.1 => 0.17.3
- perf: 1.0 => 1.1
- psutil: 5.2.0 => 5.2.1

--------------------------

* Upgrade requirements:

- certifi: 2016.9.26 => 2017.1.23
- Chameleon: 3.0 => 3.1
- Django: 1.10.5 => 1.10.6
- MarkupSafe: 0.23 => 1.0
- dulwich: 0.16.3 => 0.17.1
- mercurial: 4.0.2 => 4.1.1
- pathlib2: 2.2.0 => 2.2.1
- perf: 0.9.3 => 1.0
- psutil: 5.0.1 => 5.2.0
- SQLAlchemy: 1.1.4 => 1.1.6

--------------------------

* Fix Windows support (upgrade perf from 0.9.0 to 0.9.3)
* Upgrade requirements:

- Chameleon: 2.25 => 3.0
- Django: 1.10.3 => 1.10.5
- docutils: 0.12 => 0.13.1
- dulwich: 0.15.0 => 0.16.3
- mercurial: 4.0.0 => 4.0.2
- perf: 0.9.0 => 0.9.3
- psutil: 5.0.0 => 5.0.1

--------------------------

* Add ``mdp`` benchmark: battle with damages and topological sorting of nodes
in a graph
* The ``default`` benchmark group now include all benchmarks but ``pybench``
* If a benchmark fails, log an error, continue to execute following
benchmarks, but exit with error code 1.
* Remove deprecated benchmarks: ``threading_threaded_count`` and
``threading_iterative_count``. It wasn't possible to run them anyway.
* ``dulwich`` requirement is now optional since its installation fails
on Windows.
* Upgrade requirements:

- Mako: 1.0.5 => 1.0.6
- Mercurial: 3.9.2 => 4.0.0
- SQLAlchemy: 1.1.3 => 1.1.4
- backports-abc: 0.4 => 0.5

--------------------------

* Add ``sqlalchemy_imperative`` benchmark: it wasn't registered properly
* The ``list`` command now only lists the benchmark that the ``run`` command
will run. The ``list`` command gets a new ``-b/--benchmarks`` option.
* Rewrite the code creating the virtual environment to test correctly pip.
Download and run ``get-pip.py`` if pip installation failed.
* Upgrade requirements:

* perf: 0.8.2 => 0.9.0
* Django: 1.10.2 => 1.10.3
* Mako: 1.0.4 => 1.0.5
* psutil: 4.3.1 => 5.0.0
* SQLAlchemy: 1.1.2 => 1.1.3

* Remove ``virtualenv`` dependency

--------------------------

* Fix setup.py: include also ``performance/benchmarks/data/asyncio.git/``