email: fix fallback sending to multiple admins If no recipients are set, emails are sent to all admins and the address specified in the config file setting 'email_to'. However, the existing code did not cater for the fact that multiple addresses could be set there: the setting was treated as a single string and passed along as-is. Adapt the code to split the email_to contents on a comma, as this is the separator expected by backlash.

[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