The docs sometimes referred to "accelerated mode" as "accelerate mode".
This patch changes it to "accelerated mode" everywhere.

Also removing cruft code from earlier iteration on task.py and fixing
a bug where 'shell' was not removed from the task ds after munge()
cleaned things up

Also reworking tests to cut down on the number of patches required
by sub-classing the DataLoader() class and reworking the base object's
structure a bit to allow its use

Update playbooks_variables.rst

As per yum module documents it state only support 'present, absent and latest'

Current intro doc is pointing older way of using yum module.

* added ability to set parents (will be used when the deps are loaded)
* added role caching, so roles are not reloaded needlessly (and for
  use in detecting when roles have already been run)
* reworked the way metadata was stored - now individual attribute fields
  instead of a dictionary blob

Update playbooks_roles.rst

Typo fix in playbooks_intro.rst

Ignore compiled Python for documentation.

Update developing_modules.rst

Fix the synopsis in ansible-pull man page.

Small punctuation/grammar fix.

When running `ansible-doc --list` a lot of errors are
generated when `ansible-doc` tries to find documentation
strings in `.pyc` files.

There is some kind of duplicated content with http://docs.ansible.com/faq.html#how-do-i-loop-over-a-list-of-hosts-in-a-group-inside-of-a-template and this gotcha isn't listed here.

Fixes #9316

Fixes #9399

This reverts commit a6029264.

Fixes #9400