some file format spec problems with the OOXML chart import/export

Hey,

so I have been fixing some chart OOXML issues recently and there are
some general problems.

There are a number of comments like (from typegroupcontext.cxx:147)
    // default is 'false', not 'true' as specified
but testing this in Excel showed that Excel respects the standard in
contrast to our import and export. Does anyone know why these comments
have been introduced or does anyone have a reason why we should not
fix this stuff? I already fixed a few of these problems that made my
simple test document look awful when being imported into Excel.

If there is nobody opposing it I will slowly fix these issues in the
chart import/export where I see them. Sadly there is no way to
automatically test these things as they are wrong in the import and
the export filter. The only way is to check the OOXML standard and
check how our exported documents look in MSO.

Regards,
Markus