this was hiding issues
added PubKey and PrivKey tags to the list
added PubKey to the PGPPacket factory; added stub for class PubKey(Packet)
commented out PGPKeyLoader for the time being
renamed self.payload to self.packets; changed type from collections.OrderedDict to simple list
more new test data
removed test_PGPKeyLoader for now
updated test_PGPSignature
started test_PGPKeys
added some skeleton to test_PGPKeyCollection, for later