* 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.
* import-key.py: fixed a minor typo.
* pmkey-import.py: locates and imports keys from the ProtonMail keyserver.
* pmkey-import-alt.py: the same as the previous except with setting an
alternative $GNUPGHOME directory.
