Revert "pyximport: parse distutils config files (except local setup.cfg)"

This reverts commit 813ff05a80cef908704488e660fa07d49feb8a92.

This was an accidentally applied twice.
use all distutils config files

It is very astonishing to a user, that pyximport uses a different
set of config files from the underlying distutils.
Ignore any unused entry that starts with '_'.

This makes it possible to follow PEP8 which recommends '__',
and to name unused entries, e.g.:

    foo, _bar, _zed = func()
exclude old IPython versions from IPythonMagic tests
explicitly reject unknown compiler options to make cythonize() less unfriendly to use
exclude Tests packages from coverage analysis

--HG--
extra : amend_source : 44298a4bc8ecb8fcc729f7b741ecedd6ad4200b3
include more Cython modules in coverage analysis
avoid test dependency on IPython's "nose" test helpers
simplify IPython %%cython_inline implementation; avoid unnecessary global import
make sure pyximport gets installed on %%cython_pyximport even if it was already imported
exclude currently empty Cython.Runtime package from coverage report

--HG--
extra : amend_source : 8230801cb0e5cff944c0a7b4cbd0718f28cb344e
include Cython.Compiler.Options module in coverage report
update Sphinx conf
link to project page and dev-docs from documentation
print error if parsing project version fails during doc build
use nicer Sphinx scheme and include Cython logo in docs
merge 0.20.x branch into master
Correctly handle `from cython.submodule comport name``.
cython submodule cimport test
Merge branch '0.20.x'

Conflicts:
	CHANGES.rst