[copyright] Add missing copyright headers

contrib/testgen/base58.py

@@ -1,3 +1,6 @@
+# Copyright (c) 2012 The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
 '''
 Bitcoin base58 encoding and decoding.
 

contrib/testgen/gen_base58_test_vectors.py

@@ -1,4 +1,7 @@
 #!/usr/bin/env python
+# Copyright (c) 2012 The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
 '''
 Generate valid and invalid base58 address and private key test vectors.