pylint: Less stricter similiarity checking.
cmdhistory: Make History more modular.
test_debug: Improve tests for qenum_key.
utils.debug: Format numbers as hex for qenum_key.
utils.debug: Add a broken qflags_key.
mainwindow: Don't ensure the completion rect is valid.

This did lead to problems if there was an exception shortly after initializing the mainwindow.