Create curse-downloader.py

usage: ./curse-downloader.py [curse url]

Example:  ./curse-downloader.py http://www.curse.com/addons/wow/bartender4

This finds and downloads the addon zip file from curse, to auto unzip, do this:

./curse-downloader.py http://www.curse.com/addons/wow/bartender4 && unzip -o *.zip