function d = data_loadings_combo(dataa) This function creates a new dataset as follows: - d starts equal to dataa(end). - d.L will be the multiplication of the L's of all dataa(i) - previous information, such as .previous_domain, will be retrieved from dataa(1) Assumptions are made: - inner dimmensions of dataa(i).L are compatible - dataa(1), dataa(2) etc have actually been generated in cascade. This function is suitable for generating PCA-LDA-transformed datasets, or recently the BSpline-LDA technique. The main point is getting loadings whose indexes are in the original domain (the previous domain of dataa(1))