Parse numbers correctly in error response. (#80)

diff --git a/whisk/client.go b/whisk/client.go
index 85ac505..58a29b7 100644
--- a/whisk/client.go
+++ b/whisk/client.go
@@ -514,8 +514,12 @@
 	Debug(DbgInfo, "HTTP failure %d + body\n", resp.StatusCode)
 
 	// Determine if an application error was received (#5)
+	buf := bytes.NewBuffer(data)
+	d := json.NewDecoder(buf)
+	d.UseNumber()
+
 	errorResponse := &ErrorResponse{Response: resp}
-	err := json.Unmarshal(data, errorResponse)
+	err := d.Decode(&errorResponse)
 
 	// Determine if error is an application error or an error generated by API
 	if err == nil {