Retention

* Install the bins from the whisper source into /opt/graphite/bin
* Put an array of storage schemas, to be written to storage-schemas.conf, in the attributes. These use etsy's known defaults for statsd, but not sure if that should be the default. 
* Restart carbon when the storage conf changes. Not sure how necesarry this is, but ideally it would run whisper-resize.py with the new defaults (and you wouldn't run out of disk space ;) )