View:onResize is called after UserView:drawFunc

Hi

I was going to put this issue in github but then realised that I'm far
behind master or last release. I'm in Ubuntu 16.04 built in Qt.

View:onResize is called after UserView:drawFunc

Test code:
```
(
v = UserView.new;

v.onResize = { | view |
    "onResize".postln;
};

v.drawFunc = { | view |
    "drawFunc".postln;
};

v.front;
)
```
This causes that custom drawing depending on the new size stay behind last
update.

Notes: The Qt way: http://doc.qt.io/qt-5/qwidget.html#resizeEvent "The
widget will be erased and receive a paint event immediately after
processing the resize event."

Is this being an issue on recent versions?

Best
Lucas