Update the plugins' cancels methods for the new platform API, which doesn't pass any args.
Merge pull request #428 from pulp/mhrivnak-231-release-notes

adding 2.3.1 release notes
Rename a logger to _logger.
Merge branch 'rbarlow-updated_cancel_api' into distributed-tasks
fixing progress report related unit tests
Merge pull request #436 from pulp/skarmark-unit-test-fixes

fixing progress report related unit tests
Merge changes from master
Merge changes from maser
Add an AUTHORS file.
Update doc versions to 2.4.0.
Check the metadata contexts that are being finalized before attempting to finalize them
Change the doc versions to 2.3.
Add comments to clarify the purpose of test cases
1053674 - implement distributor_removed on yum distributor
1046160 - giving up ownership of /var/lib/pulp/published
1042932 - Fix listings files in export distributor for both individual repos and repo groups.
Update for PR comments
Merge pull request #443 from pulp/barnabycourt-1053674

1053674 - implement distributor_removed on yum distributor
1064594 - initializing plugin loader for migration 0015
Update for PR comments