Couple of minor digital display improvements

[Starkku]

• Offset and Offset.ShieldDelta Y-axis offset behaved inconsistently compared to everything else in the game, with negative values shifting down and positive up. It now works the other way around like PixelSelectionBracketDelta, YDrawOffset etc. do.
• Added ValueScaleDivisor (taking suggestions for name) that can be used to adjust the scale of displayed values. This is given as an integer to prevent rounding issues with floating point values and is used to divide the values.