composer/composer — pull request #2585 by jaypea (2014-01-13 16:17:33+00:00)
Title: added ZipArchiver to actually compress zip files

the PharArchiver used to create zip files does not compress anything currently.
when using satis with an archive directory, this new ZipArchiver saves a ton of hard disk space when the zip extension is enabled.
fallback is the current behaviour using PharArchiver.