[Speed] performance 0.1 (and 0.1.1) release

[Victor Stinner]

Hi,

I released a first version of the Python benchmark suite. (Quickly
followed by a 0.1.1 bugfix ;-))

It is now possible to install it using pip:

   python3 -m pip install performance

And run it using:

   pyperformance run --python=python2 --rigorous -b all -o py2.json
   pyperformance run --python=python3 --rigorous -b all -o py3.json
   pyperformance compare py2.json py3.json

Note: the "python3 -m performance ..." syntax  works too.

It creates virtual environments in ./venv/ subdirectory. (I may add an
option to choose where to create them.)

performance 0.1.1 version works well on Linux with CPython. There are
some know issues on Windows:
   https://github.com/python/benchmarks/issues/5

I don't consider the PyPy support as stable yet.

I used the "performance" name on PyPI, because "benchmark" and
"benchmarks" are already reserved. The Python module is also named
"performance" and comes with "pyperformance" script.

I made a suble bugfix: requirements.txt now uses fixed version rather
than ">=min_version". For example, "perf>=0.7.4" became "perf==0.7.4".
I expect to get more reproductible benchmark results with fixed
versions.

Before a release, we should not forget to update dependencies to test
the most recent versions of Python modules and applications.

Now the development version always install performance 0.1.1 (see
performance/requirements.txt). I should fix this to install the
development version of performance/ when it is run from the source
code (when setup.py is available in the parent directory?).

Victor