0.3.0: core21 only, with support for compressing XML files unpacked from v7/v8

This release adds support for compression of unpacked XML files via the --compress-xml flag.

Note that only core21 projects are supported at this time.

WARNING: v7/v8 workservers are supported by unpacking the results-###.tar.bz2 file in place, which may double your project data size on disk. You can use the --unpack option to delete the original .bz2 file after unpacking, but this option may be unsafe. We try to verify the integrity of the new directory after unpacking and before deleting the bz2 file, but this may not be foolproof.