made path decision logic more precise
added property method __fingerprints__ as a shortcut to _keys.__fingerprints__
fixed formatting on Managed.__init__
added *args to PGPKeyring.__init__ and PGPKeyring.load, and deprecated the keys= keyword argument
updated the logic in PGPKeyring.load to work recursively and also raise a PGPError if a non-PGPKey object is loaded