Docassemble

Fixed
- Removed dependency on `sklearn`.
- Issue with unicode values in `datatype: checkboxes`.

Fixed
- Rolling backup files on S3 were copied to the wrong directory during
initialization.
- Issue with `objects from file` blocks being run repeatedly if they
are not marked as `mandatory`.

Added
- Option for using `show if` in `action buttons`.
Fixed
- Error with `pdf template file` and image inclusion introduced in
1.4.21.
- Error with `.from_url()` method of `DAFile`.

Added
- The screen parts `continue button color`, `resume button color`,
`help button color`, and `back button color`.
- The question modifiers `continue button color` and `resume button
color`.
- Additional options `labelauty` and `labelauty nota` under the
`button colors` Configuration directive.
Changed
- Items in multiple choice lists, when expressed as a dictionary, can
now include keys `css class` and `color`. The HTML element for the
item will have the `css class` as a CSS class. The `color` is
expected to be a Bootstrap color name. This will change the
background color of the HTML element, unless the element is an
`<option>` element. The `css class` and `color` keys have no effect
on combobox items.
- Buttons in `action buttons` can be modified with a `css class`.

Fixed
- Error with the `.fix_up()` method of `DAFile` introduced in 1.4.21.

Added
- The `suppress autofill` directive under `features`.
- The `grid classes` Configuration directive.
- The `alert html` and `alert container html` Configuration
directives.
Changed
- Replaced `PyPDF2` with `pikepdf`.
- Bates numbering is more efficient.
- The `section` modifier now accepts Mako templating.
Fixed
- Overzealous matching of `DAContext` variables in `data` blocks.
- Possibly remedied an inefficiency in labelauty.
- Not all object types were allowed in `data from code`.