fpspreadsheet: Activate all disabled ods date tests & fix some more issues related to inconsistent formats by Open/LibreOffice -> done to 6 errors for 1904 datemode, that's probably the best we can get.

git-svn-id: http://svn.code.sf.net/p/lazarus-ccr/svn@3138 8e941d3f-bd1b-0410-a28a-d453659cc2b4