DFU update procedure

1. Rename the "*.dfu" file as "bluecore.dfu".
2. Place the "bluecore.dfu" file that you wanna update with "NFore_dfu.exe" in the same directory.
3. Execute "NFore_dfu.exe" to start the upgrade process.
4. After finished upgrade, DFU AP will exit automatically.

COM Port : 3
Normal Mode : 38400, 8 data , No Parity Check , 1 stop bits.

DFU Mode :    38400, 8 data,  No Parity Check,  1 stop bits.
