qt: raise each new window

[efiring]

This is an attempt to make progress on #596 with a one-line change to the qt backend that adds a call to raise_(). It raises and grabs focus. I would prefer that it not grab focus, but at least on OSX I don't know how to avoid it. The present behavior on OSX is so annoying that I am willing to accept the focus grab. Contrary to what I thought, my test of the qt4 backend on Linux without this change shows that at least on my XFCE desktop, the window is already being raised, including the focus grab; so the changeset here is just making OSX behave like this Linux desktop.

I also tried the approach of using the WindowStaysOnTopHint, but the problem is that it really stays on top, and that's no good either.

[mdboom]

Is there an analogous solution for Qt4 (which is still fairly relevant given that's what Anaconda gives?)

[efiring]

It should work for both. I only have qt4 on my machine, so that is all I have tested it with. Most of qt4 support is inherited from the backend_qt5 modules.

[tacaswell]

The naming on the qt4/qt5 modules is a bit odd (sorry, that is my fault), but qt5 is the 'base' implementation and the qt4 implementations sub-classes from it and patches over the API changes (the rearrangement of Qt it self and the change in PyQt5 to use cooperative sub-classes).

[mdboom]

Backported to v2.0.x as 1c7fb5b

[QuLogic]

Backport to v2.x is actually via dee9757.