Update to 2.6.3:

2.6.3
-----------

- fix issue575: xunit-xml was reporting collection errors as failures
  instead of errors, thanks Oleg Sinyavskiy.

- fix issue582: fix setuptools example, thanks Laszlo Papp and Ronny
  Pfannschmidt.

- Fix infinite recursion bug when pickling capture.EncodedFile, thanks
  Uwe Schmitt.

- fix issue589: fix bad interaction with numpy and others when showing
  exceptions.  Check for precise "maximum recursion depth exceed" exception
  instead of presuming any RuntimeError is that one (implemented in py
  dep).  Thanks Charles Cloud for analysing the issue.

- fix conftest related fixture visibility issue: when running with a
  CWD outside a test package pytest would get fixture discovery wrong.
  Thanks to Wolfgang Schnerring for figuring out a reproducable example.

- Introduce pytest_enter_pdb hook (needed e.g. by pytest_timeout to cancel the
  timeout when interactively entering pdb).  Thanks Wolfgang Schnerring.

- check xfail/skip also with non-python function test items. Thanks
  Floris Bruynooghe.

(wiz)