Add verification of detached signatures.
Remove key comment on OpenPGP key generation.
Merge remote-tracking branch 'drebs/feature/4375-add-verification-of-detached-sig' into develop
Use 'utf-8' as default/fallback encoding.

- Also reorder stdlib imports alphabetically :)
Merge remote-tracking branch 'ivan/bug/4427_default-encoding-to-utf8' into develop
Refactor code to support parsing ascii keys.
Expose openpgp methods in keymanager.

- parse_ascii_key
- delete_key
- put_key
Add changes file.
Merge remote-tracking branch 'ivan/feature/advanced_key_management' into develop
Fold in changes
Merge branch 'release-0.3.6'