gnu: python-setuptools: remove pre-built binaries from source.

These are used to build self-extracting installers for Windows.

* gnu/packages/python.scm (python-setuptools, python2-setuptools) [source]:
  Add snippet to delete *.exe files.

gnu: python-pytest-xdist: Remove needless input python-apipkg.

* gnu/packages/python.scm (python-pytest-xdist): Remove input
  python-apipkg.

gnu: python-subunit, python-testrepository: Fix inputs

* gnu/packages/python.scm (python-subunit, python2-subunit):
  [propagated-inputs]:: Add python-extras, remove python-testtools, move
  python-testscenarios to [native-inputs].  (python-testrepository,
  python2-testrepository): [native-inputs] move python-fixtures and
  python-subunit to [propagated-inputs]

gnu: python-scripttest: Correct inputs.

python-pytest is only required for testing, not at run-time.

* gnu/packages/python.scm (python-singledispatch, python2-singledispatch):
  [propagated-inputs] Move python-pytest to [native-inputs].

gnu: python-pandas: Fix build.

* gnu/packages/python.scm (python-pandas): Add python-cython to
  native-inputs.

gnu: python-ipython: Fix build.

* gnu/packages/python.scm (python-ipython, python2-ipython) [check,
  install-doc] set PYTHONPATH prior to running tests.

gnu: python-scipy: Fix build.

* gnu/packages/python.scm (python-scipy) Use add-installed-pythonpath.  Add
  dummy newlines character to string to make emacs happy.

gnu: python-matplotlib: Fix build.

* gnu/packages/python.scm (python-matplotlib, python2-matplotlib): Correct
  inputs. [install-doc] set PYTHONPATH prior to building docs.

gnu: python-numpy-bootstrap, python-numpy: Fix build.

* gnu/packages/python.scm (python-numpy-bootstrap): Correct inputs, use
  modify-phases, add dummy newlines character to string to make emacs happy,
  set PYTHONPATH prior to running tests. (python-numpy): propagate inputs, set
  PYTHONPATH prior to building docs.

gnu: python-fonttools: Remove intervening directory in site-packges.

* gnu/packages/python.scm (python-fonttools): Add phase patch-setuppy.

gnu: python2-pysnptools: Correct inputs.

dateutil, pytz, and six do not occur in the code.

Remove python-dateutil, python-pytz, python-six from inputs;
Move python-cython to native-inputs; move python-pandas to
propagated-inputs.

gnu: python-zope-testing: Remove needless input.

* gnu/packages.python.scm (python-zope-testing): Remove
  python-zope-interface from native-imports.

gnu: python-zope-schema: Add missing inputs.

* gnu/packages.python.scm (python-zope-schema): Add python-coverage and
  python-nose to native-inputs.

gnu: python-pytest-flakes: Fix build.

* python.scm (python-pytest-flakes): Set PYTHONPATH prior to running tests.

gnu: python-pillow: Fix build.

* gnu/packages/python.scm (python-pillow)[check-installed]: Add
  installed site-package to PYTHONPATH.

gnu: python-singledispatch: correct inputs.

python-six is only required for conversion, not at run-time

* gnu/packages/python.scm (python-singledispatch, python2-singledispatch):
  [inputs] Move python-six to [native-inputs].

gnu: python-pbr: Rework bootstrapping.

For breaking the cyclic build, formerly a separate (older) version was used
for bootstrapping.  Now we use the same version just without tests and without
test dependencies.

* gnu/packages/python.scm (python-pbr-0.11, python2-pbr-0.11):
  replace by … (python-pbr-minimal, python2-pbr-minimal).
  (python-pbr) inherit from python-pbr-minimal, adding the requirements for
  testing and building the documentation.
  (python-fixtures) [native-inputs] Use python-pbr-minimal here.
  (python-testrepository): [native-inputs] Add it here, it was a missing
  dependency.

gnu: python-testrepositoryfixture: Correct inputs.

python-fixtures is required only for building.

* gnu/packages/python.scm (python-testrepository) [propagated-inputs] move
  python-fixtures to [native-inputs].

gnu: python-fixture: Enable tests.

* gnu/packages/python.scm (python-fixtures) [arguments] remove
  keyword `#:tests?`.

gnu: python-fixture: Correct inputs.

python-pbr is required only for building.

* gnu/packages/python.scm (python-fixtures) [propagated-inputs] move
  python-pbr-0.11 to [native-inputs].