* Further key checks on import:
  * Invalid revocations
  * Signatures marked as non-exportable
  * PKS subkey damage
* SKS Gossip protocol support
* Split core PGP functionality out to a standalone library
* Better signature subpacket parsing (primary UID for example).
* Better merging of signatures; need to compare subpackets on Type 4 packets
  and choose which we should use (how? most recent date?)
* Honor no-modify keyserver flag ("Brian M. Carlson" <karlsson@hal-pc.org>)
* Better txt2html routine.
* Pathfinder - graphical as well?
* Do pathlengths for similar email addresses to help aide keysigning.
  (ie "Find me the keys furthest from mine that end ox.ac.uk'")
  Suggested by Jochen Voss <voss@mathematik.uni-kl.de>.
* Resurrect statistics functionality. Add other stats. most signed? signs most?