Update cyg-get

Update cyg-get to be able to run straight after installing cyg-get, if you don't close and reopen Powershell after installing cyg-get (spawning a new Powershell within doesn't work), cyg-get doesn't work. This will make cyg-get find the cygwinsetup.exe without restarting Powershell.
@ferventcoder let me know what you think, and if you are happy, we can get this pulled in, and released.