* Stores disable_autoappupdatecheckingame in settings.
* If 'disable' is active then once you're in-game WinSparkle auto
check for updates is disabled.
* Whatever the state of the option WinSparkle auto updates are
(re-)enabled when you exit the game to Main Menu or fully.
* Using 'Help' > 'Check for updates' manually will still always work.
It has been difficult to test the code fully because it isn't easy to
get WinSparkle's registry data about last update check time set just right
to not check immediately, but to do so some reasonable time after you're
in-game and have confirmed the new option setting isn't easy.
Worst case people won't learn about an update until the next time they
run EDMC.
