FastFourierTransformer.MultiDimensionalComplexMatrix.get() is not consistent with FastFourierTransformer.MultiDimensionalComplexMatrix.set().
The set() method does not allow a null parameter to get past the first check.
The get() method allows a null parameter provided dimensionSize.length <= 1.
This seems wrong, both because it is inconsistent and because it may allow an NPE later if dimensionSize.length == 1
I took the opportunity to also simplify the initialization of the dimensionSize array, using a two passes algorithm.
The inconsistency by itself was removed by having bot set and get be no-op for null vectors