Update pinentry-mac to fix the show typing bug.
[FIX] Only accept versions of GPGTools packages which are signed with the new certificate

- Adds the fingerprint of our new certificate
- Adds many additonal checks that bail out early if anything might be fishy.
[FIX] Verify that all certificates in the chain can be trusted

- Use OS X's trust services to verify the certificate chain
- Initialize all variables to avoid potential gargabe values.