disklabel is created as per mfs on "swap".
* add -Z option: pre-zero the -F image file before use. this is necessary if
the image is to be used with vnd(4) because by default the files created
with -F have "holes" and vnd doesn't cope with that.
* support 'k', 'm', 'g' suffixes for all options which take numeric arguments.
provide strsuftoi() which performs the parsing mechanism.
* improve man page description of various options
* replace "filesystem" with "file system"
* when displaying usage for mfs, only list mfs options
* minor KNF and WARNS=2 cleanups
14929f77ab