Adding the LICENSE file to be added to each file.

LICENSE.txt

+This file is part of the ALTA library.
+
+ALTA 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.
+
+ALTA 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.
+
+We however require that you contact us for any use or modification of ALTA.
+
+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/>.
+
+Contacts:
+   - Laurent Belcour <laurent.belcour@inria.fr>
+   - Romain Pacanowski <romain.pacanowski@inria.fr>
+   - Xavier Granier <xavier.granier@inria.fr>