Check on snapshot-enable and other snapshot commands

[allmightyspiff]

$>  slcli -v block snapshot-enable 152513640 --schedule-type INTERVAL --retention-count 5 --minute 31 --hour 1 --day-of-week SUNDAY
Calling: SoftLayer_Network_Storage::enableSnapshots(id=152513640, mask='', filter='None', args=('INTERVAL', '5', 31, 1, 'SUNDAY'), limit=None, offset=None))
SoftLayerAPIError(500): SoftLayer_Network_Storage::enableSnapshots is not implemented.

Need to support snapshot creation similar to