Make LED blinking 10 times if one digit is zero

[henrikkoch]

In current version 1.14 the LED shows the voltage during power up.

Each digit of the millivolts are shown with blinks for each. But if one digit is zero then it will result in no blinks for that specific digit. This should be corrected in next version to be 10 blinks for a zero instead of no blinks at all

This should corrected in next version