make gpg encryption the default case when there is a key assigned
This referes somewhat to Ticket #1019.
I have a strong preference for True as default value for gpg_enabled. The default value is only used if there is a key assigned to a contact. Now lets assume I assigne a key to a contact, then i want to have encryption enabled, right?
Security by default is always a good idea (this could be even a marketing feature:).