pull requests: prevent adding DEFAULT user as reviewer Add a helper method to resolve reviewers, with an added check to prevent the adding of the DEFAULT user as reviewer. The __add_reviewers method, although internal, had a troubling interface where the method was responsible for resolving reviewers, but the caller was responsible for resolving mention_recipients. The method is changed to always take two sets of database User objects, leaving the resolution to the caller in both cases.

[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