Do not include the BE sum in the border if we have a Table.
Only set the table in the schueler version.

This allows more flexibility for the introduction.

Now most commands that specify a test's attribute work like
their normal TeX equivalents, like \title or \author.
They no longer need to be renewed in the document.

Always print the first page header. This prevents a bug where the
first page header including the school's logo and the name
were not printed for single page tests using the sigborder option.

The Lsg environment now sets the expected points even if it is not rendered.
This allows us to use the automatic point counting also in "schueler" versions.
All exercise points are stored in an exercise-local counter and are
persisted using refstepcounter and an appropriate label.