Hammer/Samba shadow copy support started

Samuel Greear has been working on a module to translate Hammer snapshots into Windows-style shadow copies, so a Hammer volume’s snapshots would be accessible when shared to a Windows machine, or anything that understood shadow copies, so Samba.

He’s put up his work so far; it’s not finished, but he has schoolwork to get to and wants to make it available for anyone who wants to run with it.  (say, for Summer of Code…)  Apparently the macros in the shadow_copy2 or onefs modules are similar to what a Hammer module would need…