add 2-d version of normalization

 * same code, just different rank settings
add ability to load data from a Processing output file

 * add /entry/result/data as a data path
fix order of operations

 * do dataset operations in the correct order so that the lazy
   loading mechanism prevents loading the entire dataset
improve dataset handling

 * remove assumption of IntegerDataset
improve handling of datasets

 * use holder directly instead of getDataset method