hooks/zfs: 0.14.2 version bump

Refactorized zfs code. Removed {2[rs],3}-zfs files after merging the
usefull bits into zfs.
API changed as izfs is the only requirement, no ':zfs' suffix anymore.
Now this hook will be executed if *izfs* kernel cmdline, or env variable
for that matter, is present.
README.textile: update/clean up following hooks/zfs-0.14.2
init: renamed env to ienv cmdline (+minor zfs update)
mkinitramfs-ll.conf: env to ienv cmdline rename update
hooks: header update
ChangeLog: zfs entry