The misleading date description | UTC date

[TestPolygon]

The date description says that it is the last modification date and default value is the current date.
But in fact it is last modification UTC date and default value is the current UTC date.

I think it is inappropriate behavior for a lot of end users when the script is used as a browser's script and files generetad in the users' browser. The setting the current UTC date is wrong for people that lives in non UTC time zone (that is for the most people).

I think you should note this in documentation/api_jszip/file_data.md, documentation/api_zipobject.md and add an advise in README.markdown for developers to do not forget to set manually the correct date for the end user.