gz by definition is not able to preserve the sparse nature of files. using some code from the crc project and gluing it together with our decompression code, we can re-create the sparseness of a file. one downside is the operation is a little bit slower, but i think the gains from the sparse file are well worth it in IO alone.
there are a number of todo's in this PR that would be ripe for quick hitting fixes.
[NO NEW TESTS NEEDED]
Signed-off-by: Brent Baude <baude@redhat.com>
Brent Baude