These functions are supposed to make it easy for third parties (and
QLineEdit) to implement the textAt/Before/AfterOffset functions.
Before the functions were ignoring newlines completely and thus only somewhat
useful.
Change-Id: I7136b9502a7fa6f8ad9ad7236761a34c1a7fd4da
Reviewed-by: Jan Arve Sæther <jan-arve.saether@digia.com>