Should this open pr be pulled over from execuc/u2if - i2c scanning

[freemansoft]

change _i2c_scan from doing writes to a single read #11

execuc#11

[caternuson]

Are you experiencing I2C scanning issues?

I2C scanning in general is a hack. It's not part of the I2C spec. And some I2C devices are just weird.

A write is probably more robust. It's more likely to get a NACK from devices when attempting to do a read out of no where. But there is no standard since there is no actual spec for I2C scanning.