Fix FreeBSD i386 guest_os_type
Merge pull request #126 from juliandunn/freebsd-i386-system-type

Fix incorrect FreeBSD i386 guest_os_type
[BENTO-97] Specify output_directory and add vm_name, allowing for boxes to be built in parallel.
[BENTO-97] Apply @scalp42's fixes to the i386 FreeBSD definition as well