Added a missing LICENSE header.

Author: StuntsPT

setup.py

@@ -1,5 +1,21 @@
 #!/usr/bin/python3
 
+# Copyright 2016 Francisco Pina Martins <[email protected]>
+# This file is part of structure_threader.
+# structure_threader 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.
+
+# structure_threader 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 structure_threader. If not, see <http://www.gnu.org/licenses/>.
+
+
 import sys
 try:
     from setuptools import setup