cosmetic: Update copyright statement, license notice and SPDX

Some of our files didn't have a copyright notice at all, let's add
it.  Also, update the notices in other files and ensure a SPDX
identifier is present in all but the most trivial files.

Change-Id: If7fa19ce484b415bc645e39b3d0d666b44b5f0fd
diff --git a/library/RAN_Adapter.ttcnpp b/library/RAN_Adapter.ttcnpp
index 27d22ca..30a1a9e 100644
--- a/library/RAN_Adapter.ttcnpp
+++ b/library/RAN_Adapter.ttcnpp
@@ -5,6 +5,16 @@
  * with deoded BSSAP/RANAP payload.  Use this if you want to have full control about what you transmit or
  * receive, without any automatisms in place.  Allows you to refuse connections or other abnormal behavior. */
 
+/* (C) 2017-2019 Harald Welte <laforge@gnumonks.org>
+ * contributions by sysmocom - s.f.m.c. GmbH
+ * All rights reserved.
+ *
+ * Released under the terms of GNU General Public License, Version 2 or
+ * (at your option) any later version.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
 import from General_Types all;
 import from Osmocom_Types all;