Factory uses "prefered-install" configuration when creating
DownloadManager
attach IO to DownloadManager in "package" command
removes hardcoded "prefer-source" in ArchiveManage when calling
DownloadManager
use available $io in archive
https://github.com/composer/composer/pull/2099#pullrequestreviewcomment-5318806
Describe tag names more consistently, fixes #2170
Adjust cache-dir docs, fixes #1667
Abort quickly if the only match is class= in a file
Fix a typo.
Merge pull request #2175 from Hywan/typo

Fix a typo
Merge pull request #2153 from renanbr/archive-prefer-dist

prefer-dist and archive synchronized
As preparation for composer plugins, rename custom installers to plugins
Implement a plugin manager and interface, update installer plugin tests
Plugin tests are no longer strictly installer tests
Load installed plugins at appropriate time and adapt tests accordingly
Turn EventDispatcher into generic solution handling plugins as well
Add an EventSubscriberInterface which may also be implemented by plugins
Fix typo
Plugins receive composer and io objects on construction already
Fix plugin interface usage in tests
Autoload dependencies of plugins using a pool of only the local repo