Make sure all .h files have license information
Even if they don't need it: this simplifies future audits.
diff --git a/configs/config-picocoin.h b/configs/config-picocoin.h
index 4f6f3e2..5bfccf6 100644
--- a/configs/config-picocoin.h
+++ b/configs/config-picocoin.h
@@ -1,4 +1,25 @@
/*
+ * Reduced configuration used by Picocoin.
+ *
+ * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
+ *
+ * This file is part of mbed TLS (https://tls.mbed.org)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+/*
* Reduced configuration used by Picocoin.
*
* See README.txt for usage instructions.