persistence support for debians.
* Boot parameters have to be 'persistence' and 'persistence-path'
rather than 'persistent' and 'persistent-path'.
* Backing file must be named 'persistence' rather than 'live-rw'
* Filesystem on the backing file must contain 'persistence.conf'.
Avoid rewriting of paths starting with '/cdrom/' or '/dev/'.
Try somedir/vmlinuz if somedir/vmlinuz.efi is unavailable.
Check availability of 'e2fsck' and 'resize2fs'.
Added data/tools/persistence.gz that has initialized ext3 file
system that contains 'persistence.conf' file.
Shinji Suzuki