Open-Shell-Menu private

`Open-Shell` needs to adjust itself after OS upgrade. It seems that `StartMenuHelper` registration is lost after such upgrade: http://www.classicshell.net/forum/viewtopic.php?f=7&t=8082#p34821 To fix this registration, administrator rights are required (means user interaction, UAC). While this is acceptable in consumer environment, it is typically not desired in business environment where users typically doesn't have administrator rights. This patch allows to run `Open-Shell` in silent upgrade mode that will: * check if OS version changed (otherwise end immediately) * perform OS upgrade tasks without any user interraction Such mode can be then used to create scheduled task that will run this silent upgrade check on every boot with system rights: `schtasks /Create /RU "NT AUTHORITY\SYSTEM" /SC ONSTART /TN "Open-Shell OS updgrade check" /TR "%%ProgramFiles%%\Open-Shell\StartMenu.exe -upgrade -silent"` #167