Do not test for number of properties, as this now is dynamic
Do not read out SOIL, as the changes in property handling does not
support statistics for derived results, and SOIL is now part of the
general derived results.
The test to check whether an argument was a array of timestep indices
was not good enough. Text was also interpreted as a matrix.
Typechecking of the arguments is difficult due to the lack of
documentation of the octave API
