Put a placeholder task tagging API into place.

The API doesn't work yet, but we want to have a way in place to express
task tags as we convert our tasks for Celery.
Add support for username/password authentication to MongoDB
Added summary flag for repository lists
1020549 - tar the content of the distribution directory instead of the directory.
Add directory tree of content for unit tests.
Minor code changes from pull request review
Merge pull request #668 from jdob/jdob-repo-summary

Added summary flag for repository lists
Merge branch 'master' into pulp-2.4
Merge pull request #669 from pulp/jortel-1020549

1020549 - tar the content of the distribution directory instead of the directory.
Fix nodes unit tests.
Merge pull request #671 from pulp/jorte-fix-unit-tests

Fix nodes unit tests.
Add a ReservationManager for asynchronous tasks.
Merge branch 'master' into distributed-tasks
Merge branch 'rbarlow-task_tag_api' into distributed-tasks
Unit test fix
Update for comments from pull request
Add Release Notes
Merge pull request #670 from pulp/barnabycourt-mongo-authentication

Add support for username/password authentication to MongoDB & udpate to python-pymongo 2.5.2
Add puppet file distributor to the release notes
Merge pull request #675 from pulp/barnabycourt-puppet-file-distributor

Add puppet file distributor to the release notes