Add license

LICENSE

+Copyright (C) 2009-2010 Institut de Robòtica i Informàtica Industrial, CSIC-UPC.
+Author shernand (shernand@iri.upc.edu)
+All rights reserved.
+
+This file is part of robotis_mtn library
+robotis_mtn library is free software: you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation, either version 3 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 Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>
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