Set variable names.
VariableNames for this table to a new list of names.
names is a char or cellstr vector. It must have the same number of elements as the number of variable names being assigned.
ix is an index vector indicating which variable names to set. If omitted, it sets all of them present in obj.
This method exists because the
obj.Properties.VariableNames = …
assignment form does not work, possibly due to an Octave bug.