* .: signal handling
* builder/amazonebs: Copy AMI to multiple regions
* builder/amazonebs: Add unique ID to AMI name so multiple can be made
* communicator/ssh: Ability to re-establish connection
* communicator/ssh: Download()
* packer: Communicator should have Close() method
* packer: Ui input
* packer/plugin: Better error messages/detection if plugin crashes
* provisioner/shell: Upload file
* provisioner/shell: Arguments