resize window on each corner

[Jorgen-VikingGod]

Add functionality to resize window on each side and corner and not only by QSizeGrip on BottomRight corner!

[Jorgen-VikingGod]

I did already some experiments on this task - but have currently no time to go deeper here. Maybe someone else is interested in contributing this feature?

[echopoint]

I did implement this in 2 different ways locally.. One way was a grid of resize handles overlayed on the form, and the second was just manual hotspot calculation. I'm in the middle of implementing native handling of this, but didn't get the time to dive into x11 issues just yet. If you have a preference that matches any of those let me know and I'll throw a pull request in.

[Jorgen-VikingGod]

I also tried the two ways (resize handles and by a kind of hotspots and event overloading)
But I was not happy on the resizing to top and left (had some dirty jumping effects)
To have a native implementation is surely the best solution - but I can also live with a good hotspot solution.

So bring in what you have working and I will try/test it - and merge it on master if it is working good enough for all ;)

[Jorgen-VikingGod]

on issue #11 is a great working example linked. Maybe merge in some of the key features into this example?