* 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.
* Set LaTeX headers to enable ligatures and a 12pt font by default.
* Paper size left for regional defaults.
* Using XeLaTeX for easier font control.
* Using default LaTeX font of Latin Main, but that's easy enough to change.
* Updated TODO.
* The entirety of the old TODO has been replaced with either more
relevant tasks or goals for the examples and a more measured
approach to the docs and why, in this project, Org Mode trumps reST,
even though it's Python through and through.