NE2000 device model in userspace for bhyve

by Teaca for FreeBSD

The bhyve hypervisor uses a virtio net PCI device emulation. However, a number of guest operating systems do not have virtio device drivers and are not able to use this emulation. One of the best supported devices, especially in older operating systems, is the NE2000 device. An implementation of a device model for this NIC would allow a larger number of unmodified guest operating systems to run under bhyve.