* tests/test_config.py: (TestAuthenticationConfigFile.test_unknown_password_encoding): Test that the user get a meaningful error on typos or installation problems. (TestCredentialStoreRegistry): Basic tests for the registry. (TestPlainTextCredentialStore): Test plain text credential store.
* config.py: (AuthenticationConfig.decode_password): Go through the credential store registry to decode the password. (CredentialStoreRegistry): New registry for credential stores. (CredentialStore): Abstract base class for credential stores. (PlainTextCredentialStore): Default, plain text, credential store, using authentication.conf file itself as storage(i.e actual behavior).