Built-in updater

[Korb]

In light of the problems with updating the application in some situations (#14 and #84), I suggest considering the possibility of adding a built-in update mechanism similar to the Fan Control. Fan Control is also portable and requires administrator rights, but updating is as user-friendly as possible:

1. the app displays a notification that a new version is available,
2. the user consents to the update,
3. the app launches an updater,
4. which downloads the new version,
5. unpacks it,
6. closes any current app processes,
7. copies the unpacked files to the app directory, overwriting old files and preserving user settings,
8. launches the app,
9. and the updater closes.