pytest migration: use pytest test skipping instead of nose's While the nose test skipping still worked, we want to remove all remnants of nose, so switch to the pytest equivalent. Note: due to a bug in pytest-sugar (reported at [1]) the skipped tests are not shown explicitly when using the 'skipif' approach, while they were with the nose approach. Since pytest-sugar is not enabled yet in setup.py, this is not deemed a problem. [1] https://github.com/Frozenball/pytest-sugar/issues/75

[pytest]
# only look for tests in kallithea/tests
python_files = kallithea/tests/**/test_*.py
addopts =
    # --verbose
    # show extra test summary info as specified by chars (f)ailed, (E)error, (s)skipped, (x)failed, (X)passed, (w)warnings.
    -rfEsxXw
    # Shorter scrollbacks; less stuff to scroll through
    --tb=short