Add license

Author: bobleesj

LICENSE.txt renamed to LICENSE.rst

@@ -0,0 +1,50 @@
+LICENSE
+=======
+
+This program is part of the DiffPy and DANSE open-source projects
+and is available subject to the conditions and terms laid out below.
+
+Copyright 2006-2007, Board of Trustees of Michigan State University,
+
+Copyright 2008-2012, The Trustees of Columbia University in the
+City of New York.  (Copyright holder indicated in each source file).
+
+Copyright (c) 2024, The Trustees of Columbia University in the City of New York.
+All rights reserved.
+
+For more information please visit the project web-page:
+
+    http://www.diffpy.org/
+
+or email Prof. Simon Billinge at [email protected]
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions
+are met:
+
+- Redistributions of source code must retain the above copyright
+    notice, this list of conditions and the following disclaimer.
+
+- Redistributions in binary form must reproduce the above copyright
+    notice, this list of conditions and the following disclaimer in the
+    documentation and/or other materials provided with the distribution.
+
+- Neither the name of the copyright holder nor the names of its
+    contributors may be used to endorse or promote products derived from
+    this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY COPYRIGHT HOLDER "AS IS".  COPYRIGHT HOLDER
+EXPRESSLY DISCLAIMS ANY AND ALL WARRANTIES AND CONDITIONS, EITHER
+EXPRESS OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY, TITLE, FITNESS, ADEQUACY OR SUITABILITY
+FOR A PARTICULAR PURPOSE, AND ANY WARRANTIES OF FREEDOM FROM
+INFRINGEMENT OF ANY DOMESTIC OR FOREIGN PATENT, COPYRIGHTS, TRADE
+SECRETS OR OTHER PROPRIETARY RIGHTS OF ANY PARTY.  IN NO EVENT SHALL
+COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR ANY DIRECT, INDIRECT,
+INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+THIS SOFTWARE OR RELATING TO THIS AGREEMENT, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.