Testing Qt5 on Mac

[Mojca M. <moj...@gm...>]

Hi,

just a few observations about testing Gnuplot with Qt5 on Mac:
- Printing now works (it didn't work with Qt4)
- There are now two windows in the Dock (gnuplot and gnuplot_qt) and I
don't know how to close the one called "gnuplot" (the old trick and
the sole reason why qt_term_mac.c exists doesn't work any more)
- Setting the application icon doesn't work any more
- I get the following warnings when saving files:
  QFileSystemWatcher::removePaths: list is empty
but I have no clue what they mean.

(I wasn't able to compile it before I removed Qt4 completely. When Qt4
was present, some headers from Qt4 were used instead of those from
Qt5.)

None of the mentioned is any serious issue though - I'm surprised that
it works smoothly, particularly the printing that was broken before.

Mojca