Add license to tests

tests/database_table_test.py

 #!/usr/bin/env python3
+
+'''
+Copyright (C) 2016 Centro de Computacao Cientifica e Software Livre
+Departamento de Informatica - Universidade Federal do Parana - C3SL/UFPR
+
+This file is part of HOTMapper.
+
+HOTMapper 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 3 of the License, or
+(at your option) any later version.
+
+HOTMapper 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 HOTMapper.  If not, see <https://www.gnu.org/licenses/>.
+'''
+
 '''Describes tests for the database.database_table module, concerning DatabaseTable objects
 and their manipulation'''
 import unittest