#1691 jython error when datum - rank1dataset

[Jeremy Faden]

The following code would result in an exception, when a dataset is subtracted from a datum:

ds= datum(0) - dataset([1,2,3])
for d in ds: print d

This is because PyQDataSet isNumberType would always return true, so the subtract method in PyDatum would attempt to get the float value assuming it was rank 0 data. "PyQDataSet with rank=1 found where rank 0 was expected" is seen.

The isNumberType needs to return false when the data is not rank 0.

[Jeremy Faden]

This has fixed the problem.

[Jeremy Faden]

See https://sourceforge.net/p/autoplot/bugs/1753/