[iOS] Issue with touch pressure + Fix

[antoineMica]

I'm currently working on an app based on a GameViewCotnroller + Metalkit.
I have added the Gainputview as a subview to the MTKView but I have found an issue with the function initWithFrame of GainputView when trying to detect the iOS windows.
Coming from this line:

gainput/lib/source/gainput/GainputIos.mm

Line 37 in 4973ae4

UIWindow* window = [UIApplication sharedApplication].keyWindow;

I have replaced it with:
UIWindow* window = [[[UIApplication sharedApplication] delegate] window];
And it now detects the window correctly.