Get text in all indicated consequtive lines.
Usage
rs_get_text(row, end_row = NULL, context = rs_get_context())
rs_get_selected_rows(context = rs_get_context())
rs_get_first_selected_row(context = rs_get_context())
rs_get_first_selected_row_length(context = rs_get_context())
rs_get_last_selected_row(context = rs_get_context())
rs_get_last_selected_row_length(context = rs_get_context())