SCH/PCB Final check done, Add BOM
Change LED and ADC Port configuration for board Rev C
添加Modbus代码
修改modbus port 部分代码以配合OSM Rev C.
USART DMA发送完成之后，在发送状态机中不再检查usSndBufferCount
Add modbus input reg from adc, 4bit coils for mosfet, 1bit io for discrete input.
readme， TODO 更新
delete old version firmware code and other useless doc.