revise dedication to the public domain

LICENSE.rst

@@ -2,22 +2,36 @@
 Terms of Use
 ------------
 
-This software was developed at the `National Institute of Standards
-and Technology`_ by employees of the Federal Government in the course
-of their official duties.  Pursuant to `title 17 section 105`_ of the
-United States Code this software is not subject to copyright
-protection and is in the public domain.  FiPy is an experimental
+This software was developed by employees of the `National Institute
+of Standards and Technology`_, an agency of the Federal Government.
+Pursuant to `title 17 section 105`_ of the United States Code,
+works of NIST employees are not not subject to copyright
+protection, and this software is in the public domain.  FiPy is an experimental
 system.  NIST_ assumes no responsibility whatsoever for its use by
 other parties, and makes no guarantees, expressed or implied, about
 its quality, reliability, or any other characteristic.  We would
 appreciate acknowledgement if the software is used.
 
-This software can be redistributed and/or modified freely
-provided that any derivative works bear some notice that they are
-derived from it, and any modified versions bear some notice that
-they have been modified.
+To the extent that NIST_ may hold copyright in countries other than the
+United States, you are hereby granted the non-exclusive irrevocable
+and unconditional right to print, publish, prepare derivative works and
+distribute this software, in any medium, or authorize others to do so
+on your behalf, on a royalty-free basis throughout the world.
 
+You may improve, modify, and create derivative works of the software or any
+portion of the software, and you may copy and distribute such modifications
+or works. Modified works should carry a notice stating that you changed
+the software and should note the date and nature of any such change. Please
+explicitly acknowledge the National Institute of Standards and Technology
+as the original source, by linking back to `this repository`_ or
+`the website`_.
+
+This software can be redistributed and/or modified freely provided that any
+derivative works bear some notice that they are derived from it, and any
+modified versions bear some notice that they have been modified.
 
 .. _National Institute of Standards and Technology: http://www.nist.gov/
-.. _NIST:                 http://www.nist.gov/
+.. _NIST: http://www.nist.gov/
+.. _the website: https://www.ctcms.nist.gov/fipy
+.. _this repository: https://github.com/usnistgov/fipy
 .. _title 17 section 105: http://uscode.house.gov/uscode-cgi/fastweb.exe?getdoc+uscview+t17t20+9+0++