Rebased to version 2.0.0
    Several fixes for use with bugzilla 5
    This release contains several smallish API breaks:
    Bugzilla.bug_autorefresh now defaults to False
    Credentials are now cached in ~/.cache/python-bugzilla/
    bin/bugzilla was converted to argparse
    bugzilla query --boolean_chart option is removed
    Unify command line flags across sub commands