* Fixed an issue where archive-copy would fail on an incr/diff backup when hardlink=n. In this case the pg_xlog path does not already exist and must be created. Reported by Michael Renner
* Allow duplicate WAL segments to be archived when the checksum matches. This is necessary for some recovery scenarios.
* Allow comments/disabling in pg_backrest.conf using #. Suggested by Michael Renner.
* Better logging before pg_start_backup() to make it clear when the backup is waiting on a checkpoint. Suggested by Michael Renner.
* Various command behavior, help and logging fixes. Reported by Michael Renner.
* Fixed an issue in async archiving where archive-push was not properly returning 0 when archive-max-mb was reached and moved the async check after transfer to avoid having to remove the stop file twice. Also added unit tests for this case and improved error messages to make it clearer to the user what went wrong. Reported by Michael Renner.
* Fixed a locking issue that could allow multiple operations of the same type against a single stanza. This appeared to be benign in terms of data integrity but caused spurious errors while archiving and could lead to errors in backup/restore. Reported by Michael Renner.
* Replaced JSON module with JSON::PP which ships with core Perl.
* Pushing duplicate WAL now generates an error. This worked before only if checksums were disabled.
* Database System IDs are used to make sure that all WAL in an archive matches up. This should help prevent misconfigurations that send WAL from multiple clusters to the same archive.
* Regression tests working back to PostgreSQL 8.3.
* Improved threading model by starting threads early and terminating them late.
* Added restore functionality.
* All options can now be set on the command-line making pg_backrest.conf optional.
* De/compression is now performed without threads and checksum/size is calculated in stream. That means file checksums are no longer optional.
* Added option `--no-start-stop` to allow backups when Postgres is shut down. If `postmaster.pid` is present then `--force` is required to make the backup run (though if Postgres is running an inconsistent backup will likely be created). This option was added primarily for the purpose of unit testing, but there may be applications in the real world as well.
* Fixed broken checksums and now they work with normal and resumed backups. Finally realized that checksums and checksum deltas should be functionally separated and this simplied a number of things. Issue #28 has been created for checksum deltas.
* Fixed an issue where a backup could be resumed from an aborted backup that didn't have the same type and prior backup.
* Removed dependency on Moose. It wasn't being used extensively and makes for longer startup times.
* Checksum for backup.manifest to detect corrupted/modified manifest.
* Link `latest` always points to the last backup. This has been added for convenience and to make restores simpler.
* More comprehensive unit tests in all areas.
* Complete rewrite of BackRest::File module to use a custom protocol for remote operations and Perl native GZIP and SHA operations. Compression is performed in threads rather than forked processes.
* Fairly comprehensive unit tests for all the basic operations. More work to be done here for sure, but then there is always more work to be done on unit tests.
* Removed dependency on Storable and replaced with a custom ini file implementation.
* Added much needed documentation (see INSTALL.md).
* Numerous other changes that can only be identified with a diff.
