Tksheet

Fixed:
- Issues since version `7.4.4` with `get_cell_kwargs()` leading to cell options such as dropdowns sometimes not displaying

Changed:
- Remove unused parameter `object` from `Formatter` class

Changed:
- Functions which had mutable default arguments have been changed to either have:
- no default argument where appropriate OR
- `None` as the default and create an empty mutable if `None`

Fixed:
- [267](https://github.com/ragardner/tksheet/issues/267)
- Treeview mode: changed recursive functions to `while` functions to avoid recursion depth limit during tree traversal
- Additional treeview function `move()` fixes

Improved:
- Code for `see()` and arrow key functions

Changed:
- **!:** Parameter for function `sort()`:
- `boxes` is now `*box: CreateSpanTypes`
- [More information](https://github.com/ragardner/tksheet/wiki/Version-7#sorting-cells)

Fixed:
- Sorting algorithm wasn't sorting some items correctly
- Boxes in event data not being correct when `sort()` was used
- Addressed some issues with treeview mode `move()`

Added:
- New in-built sort keys and default `sort_key` initialization and `set_options()` parameter
- `natural_sort_key`
- `version_sort_key`
- `fast_sort_key`

Improved:
- Various minor performance improvements

Fixed:
- Some functions bound using `extra_bindings()` were only called when a user performed an action, they're now always called when:
- adding rows/columns
- deleting rows/columns

Improved:
- Dropdown search fallback matching, performance

Addressed
- [269](https://github.com/ragardner/tksheet/issues/269)

Changed:
- `show_top_left` parameter now defaults to `None` to represent tksheet handling of top left visibility
- Provide `natural_sort_key` as importable from `tksheet.natural_sort_key`
- `dropdown_search_function` now uses an iterable of objects rather than an iterable of Sequences of objects
- Rename internal parameter `restored_state` -> `from_undo`

Fixed:
- Strings that started with numbers not being sorted in the correct order

Changed:
- Add file paths to sort order using pathlib
- For better backwards compatibility use the usual "move_rows"/"move_columns" event names for sorting rows/columns events

Fixed:
- Issues with `7.4.0` sorting
- [270](https://github.com/ragardner/tksheet/issues/270)
- Only add to index header when user adds rows/columns if index/header is populated