v0.4.0

feat: v0.4.0 release

- fix: update index of GeneratedImage.alt
- fix: now secure_1psidts will only be passed to cookies if it is not empty
- feat: add an optional parameter to Image.save() to skip images with invalid file names
- feat: Image.save() now returns saved file path on success
- refactor: code reorganization and cleanup
- test: updated unit tests