New:
- `Cert.signer()` now accepts a password argument for password protected files.
- `decrypt` function.
- `Cert.decryptor()` function for getting decryptor out of software keys.
- `Card.decryptor()` function for getting decryptor for OpenPGP cards.
- Add Apache 2.0 license file and project metadata.
Changed:
- `Cert` objects are now always viewed through Sequoia's `StandardPolicy`. This makes it filter out weak algorithms.
- `encrypt` supports multiple recipients.
- `Card` usage examples are now tested in CI.
- `sequoia_openpgp` now uses CNG on Windows and Nettle otherwise.
Deleted:
- `Context` object removed since now each `Cert` object contains its own policy.