LICENSE: add info about SPDX-License-Identifier usage and use it

Signed-off-by: Roger Meier <roger@bufferoverflow.ch>

XML/src/XMLString.cpp

@@ -10,27 +10,7 @@
 // Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
 // and Contributors.
 //
-// Permission is hereby granted, free of charge, to any person or organization
-// obtaining a copy of the software and accompanying documentation covered by
-// this license (the "Software") to use, reproduce, display, distribute,
-// execute, and transmit the Software, and to prepare derivative works of the
-// Software, and to permit third-parties to whom the Software is furnished to
-// do so, all subject to the following:
-// 
-// The copyright notices in the Software and this entire statement, including
-// the above license grant, this restriction and the following disclaimer,
-// must be included in all copies of the Software, in whole or in part, and
-// all derivative works of the Software, unless such copies or derivative
-// works are solely in the form of machine-executable object code generated by
-// a source language processor.
-// 
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
-// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
-// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
-// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
-// DEALINGS IN THE SOFTWARE.
+// SPDX-License-Identifier:	BSL-1.0
 //