ensure that each module has a .qmake.cache when properly qmake'd

this makes properly configured modules (whose top-level project file was
evaluated) uniformly recognizable.

Change-Id: Ib127df2becb2ff7f51ee8cc5a194ff168b41c227
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>
Doc: Changed title of Qt Print Support's C++ Classes page.

-old title created broken links in Assistant.
-conforms to Qt 5 naming scheme.

Change-Id: Iaf619c1264edc1f9d2fd24f7031fe6c07efd2c1d
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>