Any `text_`-prefixed table extraction setting now automatically gets
passed to `.extract_text(...)` via `table.extract(...)`.
This introduces one minor but breaking change, which is that
`keep_blank_chars` (previously, a valid table extraction setting) now
needs to be passed as `text_keep_blank_chars`.
A fairly large commit, adding type annotations/hints to the entire
library, and refactoring the library accordingly.
Most of the refactoring changes should have no practical effect on
usage, but several others are notable:
- Added `TableSettings` class, a behind-the-scenes handler for managing
and validating table-extraction settings.
- Renamed the positional argument to `.to_csv(...)` and `.to_json(...)`
from `types` to `object_types`.
- Tweaked the output of `.to_json(...)` so that, if an object type is
not present for a given page, it has no key in the page's object
representation.
- Removed `utils.filter_objects(...)` and move the functionality to
within the `FilteredPage.objects` property calculation, the only part
of the library that used it.
- Removed code that sets `pdfminer.pdftypes.STRICT = True` and
`pdfminer.pdfinterp.STRICT = True`, since that [has now been the
default for a
while](https://github.com/pdfminer/pdfminer.six/commit/9439a3a31a347836aad1c1226168156125d9505f).
Jeremy Singer-Vine