Close relay when power on.
Add relay control code.
Adjust value of relay on/off
Add GUI code.
用QTimer代替原有创建进程的方式实现等间隔通信。
modbus通信内容改为三路输入寄存器，结果显示在主界面上。
Add QCustomPlot code to project.
Move Realtime plot example to project.
use QVector contain data.
use qcustomplot display data.
Add zoom and drag function.
Move system init code to mb_gui init part, left start/stop button only.
Add Data Save function and clear data window function.