Fix some bugs.
- Check operation to add is not in operation table already
- execute_by_name returns a value to indicate if operation was performed correctly or not
- Create a search_by_name operation in operation_list class to re-use it when we want to add new operation and in other functions (see caloe.c)
- Fix error messages
- Change TIMEOUT_LIMIT value to wait until operation is performed
check_write: Check write operation with UDP packets (testing...)