bug fix to get EC2 public address. automate creation of server

This PR includes one significant bug fix, which is to correct or update the URL the voodoo-vpn.sh script uses in order to retrieve the VPN server's public IP address. It was looking for an instance meta-data property called public-ipv4, which does not exist by default, but public-hostname done.

This PR also includes a new python script, which completely automates the creation of the VPN server. It uses the (standard) python boto module to script interaction with AWS and create the instance, and then uses the fixed voodoo-vpn.sh to configure the server.