* Mostly tightening up the details on the hkp4py example script.
* Also fixed a typo in the LGPL boiler plate text included in all the
other example scripts for the HOWTO.
* Example of default exporting keys.
* Example of exporting minimised keys.
* Example of exporting secret keys to a file with correct permissions.
Signed-off-by: Ben McGinnes <ben@adversary.org>