Gcapi

- Adds support for multiple polygon image answers

- Adds support for Number answers

- Adds support for Image answers
- Allows setting `content` rather than
`filename` in
`upload_files`

- Breaking Changes in `upload_cases`:

- Renamed kwarg `files_to_upload` to `files`
- `algorithm` kwarg now takes a `slug` rather than a `title`
- Removed `run_external_algorithm`, use `upload_cases` instead

- Add Multiple 2D bounding box question types to reader studies

- Add support for ETDRS grid annotation endpoints

- Skip validation of PATCH requests