Add resizing support to the core

[migueldeicaza]

Resizing of the toplevel windows, and message boxes should be relatively easy, but there is no support to relayout the views. As we do not currently have a layout system, beyond the absolute positioning system.

Update The https://github.com/migueldeicaza/gui.cs/tree/layout branch now contains a C# port of the Xamarin Flex engine that Stephane Delcroix did, while the port is complete, it is completely untested, that needs to be done.

[attilah]

Can't we use https://github.com/xamarin/flex ?

[migueldeicaza]

I have the code in a branch, have not tested it yet.

Stephane Delcroix ported Flex to C# and I adapted that port to gui.cs, check it out here:

https://github.com/migueldeicaza/gui.cs/tree/layout

[migueldeicaza]

New layout system in place, not based on Flex, which now I need to wire up.

[migueldeicaza]

Done the Linux one.