CostCenter Tag & ability to set during deploy

[RSabounds]

Deployment of EBS Snapper includes CostCenter tag, as of Issue 51 resolution:
#51

That said, it is not possible to specify the costcenter tag during deployment, nor to update it with the CLI. This requires the user to run updates to the CFN Stack manually, and to update the S3 bucket created by deploy.py for costcenter. if either of these is missed, the items will not be correctly tagged for customers managing costs.