calendar view has 1 hour offset

[HorstBaumann]

There is an myterious offset of 1hour in the calendar view.
Also on the official Demo-page: https://www.roeder-webdesign.berlin/de/dated-news/

for example: an event set on 10:30 -16:30 is shown as 9:30-15:30

[agendartobias]

This will help: #9