The following changes have been applied to the installer at
http://www.autohotkey.com/download/
Added command Drive, which ejects/retracts the tray in a CD or DVD drive, or sets a drive's volume label.
Added built-in variables A_ScreenWidth and A_ScreenHeight, which contain the width and height of the primary monitor, in pixels.
Added command SysGet, which retrieves screen resolution, multi-monitor info, the dimensions of system objects, and other system properties. [thanks Gregory F. Hogg of Hogg’s Software]
GUI: Fixed possible crash (never actually observed) when a window destroys itself, such as via a Quit button.
GUI: Fixed "Gui Show" so that when called from the tray menu (and perhaps other times), the window will have keyboard focus. [thanks Tekl]