Ironic. After all that hoo-haw about dynamically-created MBRs in the
previous commit, we introduce a new hardcoded static MBR...

Goals:
 * Single OS partition, in the fast area of rotating disks
 * Proper alignment for 4k sector drives and SSDs (1MB alignment)
 * Still works on 40GB disk (aka, pc850s)
 * P1 16 GiB: goldilocks FS: not too small (> 10GB), but not too big (< 30GB)
 * P2  3 GiB: can hold a co-loaded MBR 1 image (e.g., FBSD410 delay node OS)
 * P3  3 GiB: at least as much swap at currently (>= 1GB)

The partition table:
  P1:     2048	33554432	FS, 16GiB
  P2: 33556480	 6291456	possible delay-node OS or additional swap, 3GiB
  P3: 39847936	 6291456	swap, 3GiB
  P4: 46139392	34278848+	extrafs, 16+GB

The larger size and partition alignment are why I pushed this through despite
my noble intentions.