v1.5
replaced all power connectors except BV power and ground, lpGBT I2C
connector also replaced.
v1.6
Sensor modules' I2C masters changed to one from lpGBT and the other two
to GBT-SCA. GBT-SCA's DVDD moved to VDD power supply and the voltage is
lowered to 1.4V to make it easier for 1.2V I2C.
v1.7
WP7B connectors' center groud strip width changed from 1mm to 0.8mm
as recommended in its datasheet.