Handle Windows Data Deduplication Reparse Points

[jessek]

Windows Server 2012 can use "state-of-the-art deduplication that uses variable-chunking and compression". See http://blogs.technet.com/b/filecab/archive/2012/05/21/introduction-to-data-deduplication-in-windows-server-2012.aspx for background.

The service works in the background to compress and deduplicate files. Modified files are replaced with a small file and marked with a reparse point, IO_REPARSE_TAG_DEDUP. This reparse point is currently not supported (v4.3) and causes the following error:

foo.txt: Unknown reparse point 0x80000013, skipping

We need to add support for this reparse point. We should be able to open and process these files normally, but testing will be required.

[jessek]

Experimental fix posted to https://github.com/jessek/hashdeep/tree/deduplication.