Add support for flushing and deleting tasks.

Clean up critic issues and fix optional serial param.
Add support for flush_all_tasks and delete_all_tasks to scheduler.
Add support for deleting tasks from the queues to taskqueue.
Update the Changes file.
Update version number in dist.ini.
Drop the ability to do Module::Build in dist.ini.
Add taskqueuectl support for flushing scheduled tasks.
Add taskqueuectl support for deleting unprocessed tasks.
Update tests to match new code.
On any tests that were changed replace hokey exception testing with
Test::Exception calls.
On any tests that were changed replace ad hoc temporary file logic with
File::Temp logic.
Update version information pending new changes.
Attempt to fix Todd's deferral problem.

Correct the call to _remove_task_from_deferral_object which was missing
the task parameter.
Modify the cleanup code to continue processing if there are no in
process tasks, but there are deferred tasks.
Add unit test to verify the deferral code is working.
Fix problem with pausing.

The code to read from disk was not properly handling the resume case if
another process did the resuming.
Merge branch 'master' of https://github.com/gwadej/cPanel-TaskQueue