[HACK-3252] add create/delete disk functions

This pull requests resolves Issue #20 

Creates two new functions:
Hardware.addDisk(size)
Disk.delete()

 This is a HACKATHON ticket.

https://dataxu.atlassian.net/browse/HACK-3252
Yes, you need login. Format the drive and mount it to the file system.
It is on my TODO list after adding this feature to dxansible skytap module.