Start work on diffing and writing metadata to disk
Split hash read from file
Call functions dynamically
Walk diffed hash
Rename --save to --write
Start implementing set_metadata_on_file()

Set atime and mtime.

Unfortunately, utime() will update both atime and mtime at the same
time. Unless both values are provided at the same time, the undefined
one will be set to the current system time.

May need to unravel the functions and switch back to a monotlithic one.
Another try at restoring metadata from file
Add restore test.
Merge branch write_metadata_to_fs into feature--restore

Conflicts:
	metamonger
Large fixup commit

master and the --restore feature branch had diverged a lot and this
caused some headache. Try to fix this here.
002-restore-data.t: Tear down test env after testing