Fix rounding in BigDecimal.SetScale for golang.

Golang "floors" negative numbers to the next lower
number, while the PAP pseudo code assumes we're
dealing with Java which "floors" negatives to the
next higher number, i.e.:
Java: Floor(-4.5) == -4
Golang: Floor(-4.5) == -5

Thanks Markus!

lstgen/generators/golang/BigDecimal.go

@@ -61,9 +61,17 @@ func (d BigDecimal) SetScale(scale int, rounding int) BigDecimal {
 
 	var v float64
 	if rounding == ROUND_DOWN {
-		v = math.Floor(d.V * exp)
+		if d.V < 0 {
+			v = math.Ceil(d.V * exp)
+		} else {
+			v = math.Floor(d.V * exp)
+		}
 	} else if rounding == ROUND_UP {
-		v = math.Ceil(d.V * exp)
+		if d.V < 0 {
+			v = math.Floor(d.V * exp)
+		} else {
+			v = math.Ceil(d.V * exp)
+		}
 	} else {
 		v = math.Round(d.V * exp)
 	}
@@ -77,4 +85,4 @@ func NewFromInt(value int64) BigDecimal {
 
 func NewFromFloat(value float64) BigDecimal {
 	return BigDecimal{value}
-}
+}