Add Multiple Windows Demo

[Visssarion]

A demo showing all Window classes and their use within the main window.

Preview:

[Visssarion]

Thanks @AThousandShips , your fixes of GDScript style has been commited.

[Visssarion]

Noooooo there is more dialogue that i missed? ;-; Will look into it

[Calinou]

Looks great so far!

I wonder if this demo should be used to showcase tray icons, or whether we should use the existing Operating System Testing demo for that instead.

[Visssarion]

Looks great so far!

I wonder if this demo should be used to showcase tray icons, or whether we should use the existing Operating System Testing demo for that instead.

StatusIndicator is a separate class from OS, so I feel fine with adding it to this demo. Although that feature only working on Windows and MacOS does make it an OS specific thing.

Will make a commit later with adding tray functionality to this demo.

[Visssarion]

Status Indicator Added to Demo

[Visssarion]

9 Commits were squashed into 1

[Visssarion]

Fixed Draggable Window not receiving input when cursor doesn't overlap window.