Properly set reply.Result to output of unmarshalled GetTxOutResult JSON.

Fix panic caused by nil pointer dereference.

Create new error type for invalid tx vout (gettxout).

jsonerr.go

@@ -148,6 +148,10 @@ var (
 		Code:    -5,
 		Message: "No information about newest block",
 	}
+	ErrInvalidTxVout = Error{
+		Code:    -5,
+		Message: "Ouput index number (vout) does not exist for transaction.",
+	}
 	ErrRawTxString = Error{
 		Code:    -32602,
 		Message: "Raw tx is not a string",

jsonresults.go

@@ -607,11 +607,11 @@ func ReadResultCmd(cmd string, message []byte) (Reply, error) {
 	case "gettxout":
 		var res *GetTxOutResult
 		err = json.Unmarshal(objmap["result"], &res)
-		if err == nil {
+		if res != nil && err == nil {
 			if res.ScriptPubKey.Addresses == nil {
 				res.ScriptPubKey.Addresses = []string{}
 			}
-			result.Result = true
+			result.Result = res
 		}
 	case "getwork":
 		// getwork can either return a JSON object or a boolean