port.config.rts not working, individual control of RTS and break operation require

[pravinkpatel]

port.config.rts= SerialPortRts.on not working, I need to use port.config=_config to get effect on RTS pin, Other most important things is, while we set/reset TXD using start/end break operation, it should not get change when we use port.config=_config, right now TXD get high when we use port.config=_config,

[mingpepe]

Please check #24 , it shoud be the same problem.