Date conversion uses different timezones for both directions

[joha78]

LocalDateConverterFactory uses UTC on one side and local timezone on the other side.

[joha78]

A pull request with fixes and additional converters: #44

[hendrikebbers]

Infos about JS time: https://www.w3schools.com/js/js_date_formats.asp

[hendrikebbers]

Maybe we should change our format to "yyyy-MM-dd'T'HH:mm:ss.SSSXXX"
See https://docs.oracle.com/javase/7/docs/api/java/text/SimpleDateFormat.html
We need to check what we need to do in JS to always get dates in this format.
@giftkugel @madmas ???