Fix the GenericI386 description:  install the kernel,
include a basic fstab and rc.conf.
Remove the customize_boot_partition hook for now.
Mostly-working VMWare guest builder.

To use this, you'll need a config file something like:

   board_setup GenericI386
   option VMWare-guest

This could certainly be improved.
Sketch the Parallels guest builder.
VMWare tweaks