Configmanager

Allow customisation of Item retrieving and setting to an extent that underlying items are completely hidden from the interface, and user just works with item values.


config = Config({'greeting': 'Hello'}, item_getter=lambda item, section: item.value)
assert config.greeting == 'Hello'

Allow Sections to be created on their own.

Allow to combine multiple `Config` instances into one, and handle it well in hooks by allowing sub-configs to manage their stuff independently.

Completely rewritten configuration declaration parser. This fixes nested ordered declaration parsing and allows less flexibility in favour of interface consistency: Lists of tuples mean sections, otherwise lists mean item default value (including empty lists). Empty dictionaries mean item default value, non-empty dictionaries mean sections.

* Adds `flat=True` keyword argument to both `load_values` and `dump_values`
* Adds `str_path_separator` setting

All iterators accept key= function (not just string)