multiple volume support and esx functionality

[logicminds]

guest.rb seems to be marked as a binary file in your branch. I tried to add/remove but it still comes up as binary.

Just tested this on esx and works great. Will need to test on other hypervisors though. You might have to copy everything in the vmware guest to other hypervisor guests.

please see the to_volume function in virt/guest.rb and virt/vmware/guest.rb.