Added NOTICE file as discussed previously on the development list

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@276022 13f79535-47bb-0310-9956-ffa450edef68

NOTICE

@@ -0,0 +1,20 @@
+   =========================================================================
+   ==  NOTICE file corresponding to the section 4 d of                    ==
+   ==  the Apache License, Version 2.0,                                   ==
+   ==  in this case for the Apache Ant distribution.                      ==
+   =========================================================================
+
+   This product includes software developed by
+   The Apache Software Foundation (http://www.apache.org/).
+
+   This product includes also software developed by :
+     - the W3C consortium (http://www.w3c.org) ,
+     - the SAX project (http://www.saxproject.org)
+
+   Please read the different LICENSE files present in the root directory of
+   this distribution.
+
+   The names "Ant" and  "Apache Software Foundation"  must not be used to
+   endorse  or promote  products derived  from this  software without prior
+   written permission. For written permission, please contact
+   apache@apache.org.