Print: enable the vector table print only for Qt5.0 and newer

In #671 a user reported that the table print outputs a blank page if there
are dives for one page or less to be printed.
This doesn't really makes any sense.

A possible bug in Qt4's QPicture is suspected, so we only enable the
vector print for Qt 5.0 and newer versions.

See #671

Signed-off-by: Lubomir I. Ivanov <neolit123@gmail.com>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>