[Lookup] Lookup now has optional 'skip_zero' constructor flag.
[Lookup] Lookup now has optional 'skip_zero' constructor flag.

- Determines whether first lookup.id(value) is 0 or 1.
- Starts at 0 by default.
- Starts at 1 if &skip_zero is passed to constructor.
- Previously always started at 1.
- Starting at 0 is useful to have ID match index.
- Starting at 1 is useful when 0 should indicate null or missing.

AbePralle/Rogue,Plasmaworks/Rogue,Plasmaworks/Rogue,Plasmaworks/Rogue,AbePralle/Rogue,Plasmaworks/Rogue