FIX: Added missing lib4neuro namespace to the exception throw.

src/General/ExprtkWrapper.cpp

@@ -17,7 +17,7 @@ BOOST_CLASS_EXPORT_IMPLEMENT(ExprtkWrapper);
 ExprtkWrapper::ExprtkWrapper() {
     // Because of serialization
     // TODO implement?
-    throw NotImplementedException();
+    throw lib4neuro::NotImplementedException();
 }
 
 ExprtkWrapper::ExprtkWrapper( std::string expression_string ) {