Recommendation is to avoid using the year nomenclature as this
information is already encoded in the git repo. Avoids needing to
repeatly update.
Also updates AUTHORS.txt from current repo with contributor names
To represent KiCad's internal units (1 nm), it's enough to have:
- 6 decimal digits in mm;
- 8 decimal digits in inches.
There's not much point in reducing the precision.
Up to 10 digits allowed just in case.
Also changes precision to 6 decimal digits by default.
