QueryModel::setHeaderData is no longer usable with 3 arguments
using WAbstractTableModel::setHeaderData does cause the 2-argument version to be exposed in
QueryModel, but default arguments to virtual functions have to be repeated if we want to use the 3-argument version.
Default arguments on virtual functions are a bad idea in general, and mixing overloading and inheritance can also be a world of pain, but we're stuck with it now.
This regression in Wt 4.5.1 was reported on the blog.