Tksheet

Changed:
- The following `MainTable` attributes are now simply `int`s or `str`s which represent either pixels or number of lines, instead of `tuple`s:
- `default_header_height`
- `default_row_height`
- `Sheet()` init keyword argument `default_row_index_width` now only accepts `int`s
- Simplify internal use of `default_header_height`, `default_row_height`, `default_column_width`, `default_row_index_width`
- Move the following attribute locations from `MainTable` to `Sheet.ops`:
- `default_header_height`
- `default_row_height`
- `default_column_width`
- `default_row_index_width`
- Removed some protections for setting default row heights, default column widths smaller than minimum heights/widths

Added:
- Functions to address issue [212](https://github.com/ragardner/tksheet/issues/212):
- `get_text_editor_value`
- `close_text_editor`

Fixed:
- Issue 210

Fixed:
- Additional header cells being created when using `set_data()` or data setting using spans under certain circumstances
- Additional index cells being created when using `set_data()` or data setting using spans under certain circumstances

Added:
- `Sheet.reset()` function

Fixed:
- Some classifiers in `pyproject.toml`

Added:
- Parameter `emit_event` to the functions:
- `span`
- `set_data`
- `clear`
- `insert_row`
- `insert_column`
- `insert_rows`
- `insert_columns`
- `del_row`
- `del_column`
- `del_rows`
- `del_columns`
- `move_rows`
- `move_columns`
- `mapping_move_rows`
- `mapping_move_columns`

- Attribute `emit_event` to Span objects, default value is `False`
- Functions `mapping_move_rows` and `mapping_move_columns` to docs

Changed:
- Functions renamed:
- `move_rows_using_mapping` -> `mapping_move_rows`
- `move_columns_using_mapping` -> `mapping_move_columns`
- Order of parameters for functions:
- `mapping_move_rows`
- `mapping_move_columns`

Changed:
- `Sheet()` initialization parameter `row_index_width` renamed `default_row_index_width`
- `set_options()` keyword argument `row_index_width` renamed `default_row_index_width`
- Move doc files to new docs folder
- Delete `version.py` file, move `__version__` variable to `__init__.py`
- Add backwards compatibility for `Sheet()` initialization parameters:
- `column_width`
- `header_height`
- `row_height`
- `row_index_width`

Removed:
- Function `cell_edit_binding()` use `enable_bindings()` instead
- Function `edit_bindings()` use `enable_bindings()` instead

Fixed:
- Error when closing a dropdown in the row index
- Menus modified for every binding for one call of enable/disable bindings with more than one binding
- Editing the index/header cells being allowed when using `enable_bindings("all")`/`enable_bindings()` when it's not supposed to

Changed:
- `Sheet()` initialization parameter `column_width` renamed `default_column_width`
- `set_options()` keyword argument `column_width` renamed `default_column_width`
- `Sheet()` initialization parameter `header_height` renamed `default_header_height`
- `set_options()` keyword argument `header_height` renamed `default_header_height`
- `Sheet()` initialization parameter `row_height` renamed `default_row_height`
- `set_options()` keyword argument `row_height` renamed `default_row_height`
- `Sheet()` initialization parameter `auto_resize_default_row_index` renamed `auto_resize_row_index`
- `set_options()` keyword argument `auto_resize_default_row_index` renamed `auto_resize_row_index`
- `Sheet()` initialization parameter `enable_edit_cell_auto_resize` renamed `cell_auto_resize_enabled`
- `set_options()` keyword argument `enable_edit_cell_auto_resize` renamed `cell_auto_resize_enabled`
- Moved most changable sheet attributes to a dict variable named `ops` (which has dot notation access) accessible from the `Sheet` object
- The order of parameters has been changed for `Sheet()` initialization
- `Sheet` attribute `self.C` renamed `self.PAR`
- Various widget attributes named `self.parentframe` have been renamed `self.PAR`
- Return key on cell editor will move to the next cell regardless of whether the cell was edited
- Parameters for classes `TextEditor`, `TextEditor_`, `Dropdown
- Bindings for cut, copy, paste, delete, undo, redo no longer use both `Command` and `Control` but either one depending on the users operating system
- Internal arrow key binding methodology, if you were previously using this to change the arrow key bindings see [here](https://github.com/ragardner/tksheet/wiki/Version-7#changing-key-bindings) for info on adding arrow key bindings

Added:
- A way to change the in-built popup menu labels, info [here](https://github.com/ragardner/tksheet/wiki/Version-7#sheet-languages-and-bindings)
- A way to change the in-built bindings for cut, copy, paste, delete, undo, redo, select all, all the arrowkey bindings and page up/down, info [here](https://github.com/ragardner/tksheet/wiki/Version-7#changing-key-bindings)