Unmount handling (#65)
Unmount handling (#65)

* unmount is failing to flush buffered data to the target machine.
- add more error handling/logging to unmounts to collect diagnostics
- claim the disk before we write to it.
- add unmount whole disk and eject at the end.

ASR is also having some problems with unmounts, so:
- retry asr runs if they fail.

* Unmount and eject whole disk when finished with it, to force all buffered updates to be flushed out to the TDM volume.

* Update ImageSessionServer.m

* We've seen occassional unmounts fail because spotlight was accessing the volume.
Tell spotlight not to index the volume when we mount it.

* Update ImageSessionServer.m

* Convert some if blocks to one liners.

google/restor