A comment like "// Root was generated 2019-06-11 16:27:04 by tir on hayiti." is added to the code when generate go structs from xml. However, in a batch-like operation (iterate xml files in a directory), even 1 xml file changes, we will see update in every file, which is not friendly to a git commit. Compared to timestamp, sometimes version is more useful as features are always binded to a specific version. It will be nice if a feature switch is provided to let users choose which comments they prefer.