v4.0.1

• rename build variant headers to avoid confusion with with used traditional, basic or script builders.
• fix a cache bug, which prevented \cite completions of recently added bibliographies from being available.
• drop another ST2 hack
• rename _InputQuickpanelListener listener to InputQuickpanelListener as ST4 ignores everything starting with underscore.
• reformat codebase using python black (should have happened before 4.0.0, but yeah)