dfxml_tool: Report ctime and crtime; optionally output ISO-8601

The timestamp reporting logic is abstracted out to a function for
optional directory reporting (coming next patch).

Signed-off-by: Alex Nelson <a.nelson@prometheuscomputing.com>
dfxml_tool: Optionally record directories

This improves comparability of dfxml_tool's output with Fiwalk.

Signed-off-by: Alex Nelson <a.nelson@prometheuscomputing.com>
Include additional file metadata

This includes the inode number and partition number, useful for
comparing results with Fiwalk.

Signed-off-by: Alex Nelson <a.nelson@prometheuscomputing.com>
dfxml_tool: Add alternative file path simplifier

This is useful for stripping path prefixes from multiple mounts added
at the same directory, e.g. '/Volumes/foo[12]' on OS X.

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