remove destructive VirtualBox networking setup

Setting up VirtualBox host-only networking for BCPC was destructive in
that it removed all interfaces and assumed that the only interfaces
available were to be used by BCPC.

This incremental changes removes the destructive nature of the host-only
networking setup.  A separate commit will provide a more intelligent
mechanism for creating the only interfaces if it does not already exist.
 As a by product, the Windows path for setting up the host-only
 interfaces has also been removed.
dynamically setup VirtualBox networking

If an existing interface exists and is configured already for the
network, store the respective interface name; otherwise, a new interface
is created and configured.