Fix load_trajectory

[maximilian-gelbrecht]

Just fixing a bug due to a change in NCDatasets

[milankl]

I thought we had a test for this function?

[maximilian-gelbrecht]

We have one which tests it for the time variable. This one was also not affected, and the routine never returned an error.

Before [:] returned the dataset as an Array in its regular shape (similar to how the Python netCDF library works (from memory)). Now [:] returns it as a Vector so like indexing a regular n-d Array with [:] and Array is the correct command. The tests just have one test for returning the correct time axis from the dataset. Time is always a vector, so this yielded no error.