gpgme 1.5.1

Big version bump for gpgme, and nudges it over to requiring gpg2 rather than gpg. The build documentation for gpgme have been strongly recommending this for quite some time, and MacPorts, Debian and Ubuntu made this change a while back. 

Revisions to all dependents given the major change.
Fixed now, I think? I got sloppy with the rebase patch, Apologies.