Cancel all tasks in an AvailableQueue before deleting it.
Add log messages when we delete a queue and when we cancel tasks.
Merge branch 'distributed-tasks' into rbarlow-babysit_fail_removed_queue_tasks

Conflicts:
	server/pulp/server/async/tasks.py
Updated the TaskStatusManager tests to reflect the new required queue parameter.

Also, moved test_task_status_manager.py to a more descriptive location.
Added tests and fixed bugs for the pulp.server.async.tasks module.
Added a test module for pulp.server.db.model.dispatch.
Merge pull request #729 from pulp/mhrivnak-supportedversion

correcting the supported OS versions in the install docs
Fix some broken unit tests.
Add cancel facility.
Better naming.
refit content sources to use cancel facility.
simpler version.
refit unit tests.
Update style guide for test directory structure
Fix line break
Tighten up the wording
Don't run devel tests on python 2.4
pass an event instead of using Call.
Update for PR comments
Merge pull request #736 from pulp/barnabycourt-update-test-convention-styleguide

Update test convention and line length styleguide