#50 Enhance key verification dialog

When I chat for the first time with another user of pidgin-encryption, a dialog box appears asking me whether I want to trust their key. The current form of this dialog makes it difficult to answer that question and verify the key fingerprints via a side channel. It would be extremely useful at this point to 1) see one's own fingerprint, too and 2) be able to copy both FPs from the dialog via copy&paste. The OTR plugin may serve as an example for such improved usability in this regard.