Added A_OSVersion value
Changed the Hotkey command to apply/remove passthrough behavior on existing hotkey variants depending on whether the tilde (~) prefix is present.
Changed exe manifest to allow GetVersion/GetVersionEx to detect Windows 8.1. Due to changes in the way these functions work as of Windows 8.1, it is likely that explicit support will need to be added to AutoHotkey for each new version of Windows; until such support is added, GetVersionEx (and therefore A_OSVersion) will return the highest supported version number when running on even newer versions of Windows.
WIN or LEARN.