Include other compressors like XZ for smaller size and LZO for speed #114
Description
Although Attic make a good job deduplicating data, it seems it uses a simle deflate method for compression (like the ones of zip and gzip).
However for data that is going to be backup once for the long term, it makes sense to take a different approach. XZ (Parallel lzma as in zbackup) is in my opinion one of the best compression you can get to further reduce the size at the expense of more cpu and extra time to encrypt and only a little bit more work to restore. For low-end computers or quick short term backups, LZO is the way to go, it's much much faster during compression and decompression at the expense of smaller compression rate.