Check if your script are running in administrator context

Doing system changes via a script files will often require that you run it in the context of administrator.

Doing this with script I run myself is easy enough, I know that if it fails it is because I forgot to use "Run as administrator" when I started it (or did a poor job creating the script).
However when creating scripts that other people will run it will be a good idea to add a check in the script and give feedback to the person running it.