Changes

* <span style="color:red;">'''Please be sure to install the X728 and Raspberry Pi in the correct order. The copper pillars must be fixed before installing the x728. Avoid short circuit caused by the X728 board touching the USB connector of the motherboard, which may cause the chip to be burned.

* <span style="color:red;">'''Never make wrong polarity connection when charging and discharging battery packs. Always double check polarity of battery's connector to make sure "+" to "+" and "-" to "-". '''

===X728 V2.2===