Resizing of axes causes 'bouncing' of axes

[astrofrog]

This is a bit hard to describe in words but when resizing a window, sometimes it looks as though the axes itself are resized faster than the actual Qt window:

This looks a bit weird when using interactively. Now I originally thought this was related to how fast axes are drawn but actually this can't be the case since the axes are actually following the cursor better than the Qt window. Maybe there is a Qt setting related to making things smooth?

@ChrisBeaumont - do you know off the top of your head what could be causing this? If not, I can dig deeper into it.

[astrofrog]

Note, the axes are a bit slow to update, but it's more that the axes and window aren't in sync

[astrofrog]

This was fixed in #745