enhance documentation

Author: Evelyn-M

climada/entity/exposures/entity_OSM.py

@@ -1,10 +1,16 @@
-#!/usr/bin/env python3
-# -*- coding: utf-8 -*-
 """
-Created on Fri Apr 26 11:29:44 2019
-Function to download "zero value" or "low value" regions from OSM
-@author: evelynm
+This file is part of CLIMADA.
+Copyright (C) 2019 ETH Zurich, CLIMADA contributors listed in AUTHORS.
+CLIMADA 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, version 3.
+CLIMADA 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 CLIMADA. If not, see <https://www.gnu.org/licenses/>.
 """
+
 import os
 import fiona
 from fiona.crs import from_epsg