added LICENSE

LICENSE

@@ -1,3 +1,34 @@
+#  This is a source file distribution of XSCHEM,
+#  a schematic capture and Spice/Vhdl/Verilog netlisting tool for circuit 
+#  simulation.
+#  Copyright (C) 1998-2020 Stefan Frederik Schippers
+# 
+#  This program is free software; you can redistribute it and/or modify
+#  it under the terms of the GNU General Public License as published by
+#  the Free Software Foundation; either version 2 of the License, or
+#  (at your option) any later version.
+# 
+#  This program is distributed in the hope that it will be useful,
+#  but WITHOUT ANY WARRANTY; without even the implied warranty of
+#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#  GNU General Public License for more details.
+# 
+#  You should have received a copy of the GNU General Public License
+#  along with this program; if not, write to the Free Software
+#  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+
+
+# This software uses scconfig (http://repo.hu/projects/scconfig/) for
+# configuration and install from sources (Copyright (C) 2009..2019  Tibor Palinkas)
+# Most source files under the scconfig/ directory are released under the
+# GNU Lesser General Public License version 2 (GNU LGPL2 or later versions).
+# For details consider the explicit copyright banner in each source file.
+# for files without Copyright and license information consider:
+#   Copyright (C) 2009..2019 Tibor Palinkas and license GNU LGPL2 (or
+#   later versions of the GNU LGPL).
+# See file scconfig/COPYING for details.
+
+
                     GNU GENERAL PUBLIC LICENSE
                        Version 2, June 1991