Error when summing empty multidimensional intervals

[MaxGaukler]

The handling of empty intervals does not work for nonscalar values.

>> interval([1 2], [3 4]) + interval([4 3], [2 1])
Left limit larger than right limit
Error using  + 
Matrix dimensions must agree.

Error in  +  (line 56)
    res.inf = res.inf + summand.inf;

(I guess that the interval constructor should error if left limit > right limit.)

[wetzlingerm]

The initialization of an empty interval (in case the lower bounds are larger than the upper bounds) is utilized in some parts of the code. The proposal to throw an error will be implemented in the next release version, as this change requires major adjustments.