create a higher rank dataset with dim 1 being a bundle dimension. Each
dataset must have the same length.
Note this was created before BUNDLE_1 and bundle descriptor datasets were
introduced, so this code is suspect. TODO: review and ensure compatibility
with updates to bundle dataset semantics.
Copied from JoinDataSet in June 2009
Modification History:
- 2012-07-17: allow rank 2 datasets to be bundled. TODO: really? code doesn't look like it!
- See https://sourceforge.net/p/autoplot/feature-requests/267/