Batch processing

This adds batch processing: Creation of multiple VMs with minor differences in settings.

JBremer: Maybe you want to achieve the same goals differently (*). In that case, just use this code as inspiration.  IMHO a separate config file listing the machines and machine specific settings is a very good solution. But the way to do it (multiprocessing in python) seems to be a bit tricky when several machines are started at the same time: IP conflicts. I quick-fixed it with a sleep. The proper solution is (like you said) more in the DHCP style fix.

*) I know you want to use cloning.....