Refine hive extraction
Refine hive extraction

Changes:
* Null filenames are now handled properly.
* The file pattern list is easier to read.
* Extracted hives are now named by their Fiwalk ID.

Signed-off-by: Alex Nelson <f0ff046f20ac281c773674f5b6560446de73a810@prometheuscomputing.com>

ajnelson/regxml_extractor,ajnelson/regxml_extractor