grub-bhyve-v0.30

• Add -c, --cons-dev option to choose terminal.
  This allows nmdm devices to be used by grub for output.
  Submitted by Conrad Meyer.
• Set Linux boot_params video rows/columns to 80x25. This can
  be disabled with the "-e|--evga" switch.
• Move the 32-bit flat-mode GDT to the first page in memory to
  avoid being stomped on by the decompressor in older Linux kernels.
  These two fixes allow Centos 4/5 ISOs to boot without
  triple-faulting or panic'ing with divide-by-zero errors.
• clean up command-line help, and be more FreeBSD-specific in
  the display, including printing the grub-bhyve version.