Add vndcompress(1) and vnduncompress(1) to transform filesystem/disk
images from "normal" into cloop2-format compressed images and back. 
Written by Florian Stoehr (netbsd@wolfnode.de) with some polishing
by me.

Compressed disk images can be used with the vnd(4) driver when compiled with
VND_COMPRESSION and "vnconfig -z".  Useful for creation of Live CDs/DVDs.