Add README, with copyright

README.md

+# PARTONS
+
+## Documentation
+
+See [http://partons.cea.fr](partons.cea.fr).
+
+## Release
+
+To checkout the released version, use the tag `v1.0` (or subsequent versions) of the branch `release-v1`.
+
+## Licensing
+
+Copyright (C) 2018  PARTONS team.
+Under GPLv3. See LICENSE file.
+
+## Contact
+
+See [http://partons.cea.fr/partons/doc/html/contact.html](contact page).
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