Update project structure and build process

libwallet/encodings.go

@@ -0,0 +1,16 @@
+package libwallet
+
+import (
+	"math/big"
+)
+
+func paddedSerializeBigInt(size uint, x *big.Int) []byte {
+	src := x.Bytes()
+	dst := make([]byte, 0, size)
+
+	for i := 0; i < int(size)-len(src); i++ {
+		dst = append(dst, 0)
+	}
+
+	return append(dst, src...)
+}