Merge branch 'master' into old-oop-style

.gitignore

src/@dseries/cumprod.m

src/@dseries/cumsum.m

src/@dseries/dseries.m

src/@dseries/save.m

src/@dseries/subsref.m

src/@dseries/vertcat.m

src/initialize_dseries_toolbox.m

src/read/load_csv_file_data.m

src/read/load_mat_file_data.m

src/utilities/file/check_file_extension.m

src/utilities/from/from.m

src/utilities/insert/insert_column_vector_in_a_matrix.m

...es/insert/insert_object_in_a_one_dimensional_cell_array.m

...s/insert/replace_object_in_a_one_dimensional_cell_array.m

src/utilities/is/iscellofchar.m

src/utilities/is/isdseries.m

src/utilities/is/isglobalinbase.m

src/utilities/missing/demean/demean.m

src/utilities/missing/ndim/ndim.m