* Some instructions to include are fairly obvious; as with encryption,
  decryption and signature verification.
* Some are a little less obvious.
* This includes the requests received to specifically include subkey
  management (adding and revoking subkeys on a primary key that's
  being retained.
* Added the UID equivalents to the list, as well as key selection
  matters (and may or may not include something for handling group
  lines since that involves wrapping a CLI binary).
* Key control documentation and examples requested by Mike Ingle of
  confidantmail.org.