Add float rounding function.

common.go

@@ -6,8 +6,29 @@ import (
 	"encoding/json"
 	"io/ioutil"
 	"errors"
+	"math"
 )
 
+func roundFloat(x float64, prec int) float64 {
+  	var rounder float64
+	pow := math.Pow(10, float64(prec))
+	intermed := x * pow
+	_, frac := math.Modf(intermed)
+	intermed += .5
+	x = .5
+	if frac < 0.0 {
+		x = -.5
+		intermed -= 1
+	}
+	if frac >= x {
+		rounder = math.Ceil(intermed)
+	} else {
+		rounder = math.Floor(intermed)
+	}
+
+	return rounder / pow
+}
+
 func CalculateAmountWithFee(amount, fee float64) (float64) {
 	return amount + CalculateFee(amount, fee)
 }