* The ACL formatter was mis-formatting entries which had a
user/group ID but no name. Make the parser tolerant of
these, so that old archives can be correctly restored;
fix the formatter to generate correct entries.
* Fix overwrite detection by introducing a new "FAILED" return
code that indicates the current entry cannot be continued
but the archive as a whole is still sound.
* Header cleanup: Remove some unused headers, add some that
are required with new Linux systems.
* libarchive_test program exercises many of the core features
* Refactored old "read_extract" into new "archive_write_disk", which
uses archive_write methods to put entries onto disk. In particular,
you can now use archive_write_disk to create objects on disk
without having an archive available.
* Pushed some security checks from bsdtar down into libarchive, where
they can be better optimized.
* Rearchitected the logic for creating objects on disk to reduce
the number of system calls. Several common cases now use a
minimum number of system calls.
* Virtualized some internal interfaces to provide a clearer separation
of read and write handling and make it simpler to override key
methods.
* New "empty" format reader.
* Corrected return types (this ABI breakage required the "2.0" version bump)
* Many bug fixes.
