[doc] Add license; Fix typos

doc/source/index.rst

@@ -8,7 +8,7 @@ Overview of CADBIOM
 
 CADBIOM (Computer Aided Design of Biological Models) is an open source modelling software.
 Based on Guarded transition semantic, it gives a formal framework to help the modelling of
-biological systems such as cell signaling network.
+biological systems such as cell signalling networks.
 
 Cadbiom provides:
 
@@ -64,6 +64,8 @@ Documentation
 
    dev_documentation
 
+   license
+
 
 Indices and tables
 ==================

doc/source/license.rst

+*******
+License
+*******
+
+Cadbiom is distributed with the 3-clause BSD license.
+
+::
+
+  CADBIOM (Computer Aided Design of Biological Models) is an open source
+  modelling software for cell signalling networks.
+  Copyright (C) 2009-2020  IRISA/IRSET/INRIA
+
+  This program 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.
+
+  This program 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 this program.  If not, see <https://www.gnu.org/licenses/>.