Prd 4071: Preparation fixes for case

Fixes a large crash in a obscure report (Prd-2087.prpt in golden samples) that happened because element attributes were not properly cloned and because the style-resolver's cache-key calculation was wrong.

Also adds more debug-support and cleaner toString() methods, as well as cleans the golden samples by making them show element names on groups and group-sections.

Logs from the debugger can now be diffed between the pagination stage and the printing stage. Ideally, the output is always identical (except when using page-of-pages function).