new timer

Error :

• EOK if no error.
• EARGNIL or ECHN if the _channel_ is nil.
• EINVAL if the _period_ is nil or negative.
• EUNABLE if an internal error occurs.
• ETYPE if a type error occurs. The VM will exit and more informations could be found in the log file (if activated in the debug mode level)
• EVM if a memory error occurs. The VM will exit and more informations could be found in the log file (if activated in the debug mode level).
• EFATHER if the father is incorrect. This error should never appear in this function.