cloneWithRows(dataBlob, rowIdentities)
Clones this ListViewDataSource with the specified dataBlob and rowIdentities. The dataBlob is just an arbitrary blob of data. At construction an extractor to get the interesting information was defined (or the default was used).
The rowIdentities is a 2D array of identifiers for rows. ie. [['a1', 'a2'], ['b1', 'b2', 'b3'], ...]. If not provided, it's assumed that the keys of the section data are the row identities.
Note: This function does NOT clone the