docs: add license to README

Signed-off-by: Jacopo Notarstefano <[email protected]>

README.rst

@@ -1,3 +1,25 @@
+..
+    This file is part of INSPIRE.
+    Copyright (C) 2014-2017 CERN.
+
+    INSPIRE 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.
+
+    INSPIRE 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 INSPIRE. If not, see <http://www.gnu.org/licenses/>.
+
+    In applying this license, CERN does not waive the privileges and immunities
+    granted to it by virtue of its status as an Intergovernmental Organization
+    or submit itself to any jurisdiction.
+
+
 ================
  INSPIRE-DoJSON
 ================