update the license text

COPYING.md

-The software provided here is released by the Naval Postgraduate School,
-an agency of the U.S. Department of Navy. The software bears no
-warranty, either expressed or implied. NPS does not assume legal
-liability nor responsibility for damages resulting from or connected
-with this software.
+This software was developed by employees of the Department of the Navy
+(DON) at the Naval Postgraduate School (NPS).  NPS and the DON are
+agencies of the Federal Government.  Pursuant to title 17 United
+States Code Section 105, works of DON employees are not subject to
+copyright protection in the United States and are considered to be
+in the public domain. Permission to freely use, copy, modify, and
+distribute this software and its documentation without fee is hereby
+granted, provided that this notice and disclaimer of warranty appears
+in all copies.
 
-Please note that within the United States, copyright protection, under
-Section 105 of the United States Code, Title 17, is not available for
-any work of the United States Government and/or for any works created by
-United States Government employees. This software contains work which
-was created by NPS government employees and is therefore in the public
-domain and not subject to copyright in the United States.
+THE SOFTWARE IS PROVIDED 'AS IS' WITHOUT ANY WARRANTY OF ANY KIND,
+EITHER EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING, BUT NOT LIMITED
+TO, ANY WARRANTY THAT THE SOFTWARE WILL CONFORM TO SPECIFICATIONS, ANY
+IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+PURPOSE, AND FREEDOM FROM INFRINGEMENT, AND ANY WARRANTY THAT THE
+DOCUMENTATION WILL CONFORM TO THE SOFTWARE, OR ANY WARRANTY THAT THE
+SOFTWARE WILL BE ERROR FREE. IN NO EVENT SHALL NPS BE LIABLE FOR ANY
+DAMAGES, INCLUDING, BUT NOT LIMITED TO, DIRECT, INDIRECT, SPECIAL OR
+CONSEQUENTIAL DAMAGES, ARISING OUT OF, RESULTING FROM, OR IN ANY WAY
+CONNECTED WITH THIS SOFTWARE, WHETHER OR NOT BASED UPON WARRANTY,
+CONTRACT, TORT, OR OTHERWISE, WHETHER OR NOT INJURY WAS SUSTAINED BY
+PERSONS OR PROPERTY OR OTHERWISE, AND WHETHER OR NOT LOSS WAS
+SUSTAINED FROM, OR AROSE OUT OF THE RESULTS OF, OR USE OF, THE
+SOFTWARE OR SERVICES PROVIDED HEREUNDER.
+
+Distributions of DON software should also include copyright and
+licensing statements of any third-party software that are legally
+bundled with the code in compliance with the conditions of those
+licenses.