add Licence info to documentation

README.md

@@ -33,3 +33,7 @@ $ make
 $ make install
 $ make doc
 ```
+
+# Licence
+
+_libeisdrt_ is licenced to you under the LGPL version 3 , or (at your option) any later version. see lgpl-3.0.txt or [LGPL](https://www.gnu.org/licenses/lgpl-3.0.en.html) for details

doc/mainpage.txt

@@ -112,4 +112,8 @@ int main(int argc, char** argv)
 }
 ```
 
+# Licence
+
+_libeisdrt_ is licenced to you under the LGPL version 3 , or (at your option) any later version. see lgpl-3.0.txt or [LGPL](https://www.gnu.org/licenses/lgpl-3.0.en.html) for details
+
 */