config.get('option', 'value').lower() == 'value' is just ugly and
stupid, especially for bool.
One if in basetabs:556 was also missing a comparison, leading to True
whenever the option was set.
- No idea why subclasses of ConversationTab were working before
(info_header was overriden with None in __init__)
- Or why the date parsing worked (“Exeception”)
- Some more reformatting with pylint indications
- Document each module in the tabs module
