Plugin provides a build wrapper for starting and stopping slaves on the virtual machine
Start/stop is performed by launching shell scripts (init.d, VBoxManage for example).
Each start/stop command takes a list of nodes with virtual machines as an argument.
After launching a script plugin waits for all nodes to enter an online/offline state
by periodical reconnecting to them. It's required because master doesn't know that slave
Define a wrapper command that should be used to start/stop VirtualBox. Usually it is a sort of init.d script.
Enable a build wrapper (pre- and/or post-build command). Choose needed virtual machines.