NumericProperty: use step size in de- and increment()
Numeric properties were previously incremented and decremented by 1 cast to the property's underlying type, e.g. tgt::vec2(1). That worked fine for integer-based properties, but those storing floating-point numbers could benefit from using the step value in decrement() and increment(). Now that's exactly how NumericProperty behaves.
Showing with 2 additions and 2 deletions