Allow conversion of old filesystems to use this,
if they are already at revision 1.
There probably should be an option to turn revision 0 to revision 1.
Reviewed (in part) by Manuel (bouyer@).
* deprecate register
* cleanup manpage
* remove unused docheck()
* getopt returns -1 not EOF
* put a ) in the correct place in a printf, so that the argument gets
& 0xff, not the result of printf() itself...
christos