Tksheet

Fixed:
- Error on paste into empty sheet with `expand_sheet_if_paste_too_big`
- Data shape not being correct upon inserting a single column or row into an empty sheet
- Potential for `insert_columns()` to cause issues if provided columns are longer than current number of sheet rows
- [225](https://github.com/ragardner/tksheet/issues/225) Insert columns and insert rows not inserting blank cells into header/row index, issue seen with either:
- Right clicking and using the in-built insert functionality
- Using the `Sheet()` functions with an `int` for first parameter
- Wrong sheet dimensions caused by a paste which expands the sheet
- Wrong new selection box dimensions after paste which expands the sheet
- `set_options()` with `table_font=` not working

Changed:
- `expand_sheet_if_paste_too_big` replaced by `paste_can_expand_x` and `paste_can_expand_y`. To avoid compatibility issues using `expand_sheet_if_paste_too_big` will set both new options

Improved:
- Additional protection against issue [224](https://github.com/ragardner/tksheet/issues/224) but with `auto_resize_row_index="empty"` which is the default setting

Fixed:
- Redrawing loop with `auto_resize_row_index=True` [224](https://github.com/ragardner/tksheet/issues/224)

Changed:
- Unfortunately in order to fix [224](https://github.com/ragardner/tksheet/issues/224) while using `auto_resize_row_index=True` the x scroll bar will no longer be hidden if it is not needed

Addressed:
- Issue [222](https://github.com/ragardner/tksheet/issues/222)
- Issue [223](https://github.com/ragardner/tksheet/issues/223)

Fixed:
- Massive lag when pasting large amounts of data, caused by using Python `csv.Sniffer().sniff()` without setting sample size, now only samples 5000 characters max

Changed:
- Added `widget` key to emitted event `dict`s which can be either the header, index or table canvas. If you're using `pickle` on tksheet event `dict`s then you may need to delete the `widget` key beforehand
- Added `Highlight`, `add_highlight`, `new_tk_event` and `get_csv_str_dialect` to tksheet namespace
- Some old functions which used to return `None` now return `self` (`Sheet`)
- Re-add old highlighting functions to docs
- Event data from moving rows/columns while rows/columns are hidden no longer returns all displayed row/column indexes in the `dict` keys `["moved"]["rows"]["data"]`/`["moved"]["columns"]["data"]` but instead returns only the rows/columns which were originally moved.
- Add `Shift-Return` to text editor newline bindings
- Internal `close_text_editor()` function parameters
- Function `close_text_editor()` now closes all text editors that are open

Added:
- New parameters to `dropdown()`:
- `edit_data` to disable editing of data when creating the dropdowns
- `set_values` so a `dict` of cell/column/row coordinates and values can be provided instead of using `set_value` for every cell in the span
- New emitted events - issue [223](https://github.com/ragardner/tksheet/issues/223):
- `"<<Copy>>"`
- `"<<Cut>>"`
- `"<<Paste>>"`
- `"<<Delete>>"`
- `"<<Undo>>"`
- `"<<Redo>>"`
- `"<<SelectAll>>"`

Improved:
- Dropdown box scrollbars will only display when necessary
- Some themes colors
- Old function `highlight_cells()` slight performance boost when calling it thousands of times
- Added parameters back to the functions `dropdown()`/`checkbox()` for help when writing code

Fixed:
- Error with `equalize_data_row_lengths()` while displaying a row as the header

Changed:
- Dropdown and treeview arrow appearance to triangles

Fixed:
- External right click popup menu being overwritten by internal when right clicking in empty table space
- Copying and pasting values from a single column not working correctly
- Mousewheel in header not working on `Linux`
- `get_cell_options()`/`get_row_options()`/`get_column_options()`/`get_index_options()`/`get_header_options()` values not being requested option. These functions now return a `dict` where the values are the requested option, e.g. for `"highlight"` the values will be `namedtuple`s

Changed:
- Functions `cut()`/`copy()`/`paste()`/`delete()`/`undo()`/`redo()` now return `EventDataDict` and not `self`/`Sheet`
- `get_cell_options()`/`get_row_options()`/`get_column_options()`/`get_index_options()`/`get_header_options()`, see above fix
- Clipboard operations where there's a single cell which contains newlines will now be clipboarded surrounded by quotechars

Added:
- Functions `del_row_positions()`/`del_column_positions()`
- `validation` parameter to `cut()`/`paste()`/`delete()`, `False` disables any bound `edit_validation()` function from running
- `row` and `column` keys to `cut()`/`paste()`/`delete()` events bound with `edit_validation()`

Fixed:
- Incorrect dropdown box opening coordinates following the opening of dropdown boxes on different sized rows
- Calling `grid_forget()` on a parent widget after opening a dropdown box would cause opened dropdown boxes to be hidden
- `disable_bindings()` with right click menu options such as insert_columns would disable the whole right click menu
- Removed old deprecated dropdown box `dict` values

Changed:
- To disable the whole right click menu using `disable_bindings()` it must be called with the specific string `"right_click_popup_menu"`
- themes `dict`s now `DotDict`s