More float-to-int conversions needed

[benjie-git]

I'm currently testing out updating my project to wxPython 4.2.0 on python 3.10. I've run into more methods with numerical arguments that crash when passed floats, instead of silently converting them to ints. Testing on MacOS 12.5.1, but I assume this happens on all OSes.

* Constructors for wx.Point(), wx.Size(), wx.Rect().  e.g. wx.Size(10.0, 20.0)
* __iadd__() on Point, Size, Rect.  e.g. point += (1.0, 2.0)
* Point, Size, Rect parts __iadd__().  e.g. point.x += 2.0
* Offset() and Inflate() on Rect.  e.g. rect.Offset(1.0,2.0)