Report VM clone progress

[otwieracz]

In order to prevent:
vmware-archive/rbvmomi#118
#106

Report progress during VM clone to avoid SOAP API proxy timeouts (and it's nice from the user perspective that it's just taking so long)

-----> Creating <centos-7>...
       Bringing machine 'default' up with 'vsphere' provider...
       ==> default: Calling vSphere CloneVM with the following settings:
       ==> default:  -- Template VM: xxxxxxx/vm/Templates/Linux/centos-7-server
       ==> default:  -- Target VM: xxxxxxxx/vm/TEST/test-rbvmomi-unstable-centos-7_default_1503437202177_3869
       ==> default: Progress: 11%
       ==> default: Progress: 22%
       ==> default: Progress: 39%
       ==> default: Progress: 40%
       ==> default: Progress: 50%
       ==> default: Progress: 60%
       ==> default: Progress: 70%
       ==> default: Progress: 80%
       ==> default: Progress: 90%
       ==> default: Done!
       ==> default: New virtual machine successfully cloned
       ==> default: Waiting for the machine to report its IP address...
           default: Timeout: 900 seconds