According to an email from Kurt Hornik, examples/vignettes changed to use timezone "Europe/Berlin" rather than "CET", which is not supported any more on specific debian machines.
Additionally, I included an Authors@R comment and updated the Authors field to be compatible with that.
Additionally, the package now gives a warning to the user, when provided with a non-scalar geo-location when computing the sun-positions and works with the first entry of the provided locations. This addresses a failing vignette of the downstream move package.