All v2+ callbacks can now optionally define a CALLBACK_TYPE, which
when set to 'stdout' will limit those callbacks which are used for
primary output to a single callback plugin (specified to the
TaskQueueManager object and configurable in ansible.cfg/environment)
Dynamic task includes still need some work, this is a rough first version.
* doesn't work with handler sections of playbooks yet
* when using include + with*, the insertion order is backwards
* fix potential for task lists to be unsynchronized when using the linear
strategy, as the include conditional could be predicated on an inventory
variable
