Added Get-Excuse.ps1

This is a cool little novelty script that pulls a random
excuse from a web page.

I got it from a Powershell.com email. Here is the
description from the email.

"Tired of inventing lame excuses yourself? Then here's a
script that gets you a new excuse any time you call
Get-Excuse! All you need is Internet access."

ToDo: Comment the script giving credit to it's authors.