* glom/report_builder.[h|cc]: report_build(): Return the filepath,
instead of opening it in the browser.
* glom/xsl_utils[h|cc]: transform_and_open(): Rename to transform(),
returning the filepath. Also correct some ustring filepath to std::string.
* glom/utils_ui[h|cc]: Added show_report_in_browser().
* glom/frame_glom.cc: on_menu_report_selected():
* glom/mode_data/box_data_manyrecords.cc: print_layout: Adapted.