Disallow page break in AtPageCreation

When you place an object in AtPageCreation that doesn't fit on
the current page, a page break occurs. This is not good, since it
doesn't make sense. So let's disable the break.
PlaceObject/vreference ok for absolute positioning

With vreference="bottom" you can instruct the publisher to use the
given row as the bottom reference. That is: the object is placed
at (row - hight).
Documentation + schema update
More source code translations, QA for text/columns