apt: pass child process stdout and stdout to m.fail_json() and m.exit_json().

Without this, this fails:

    - name: apt-get dist-upgrade
      action: apt upgrade=dist
      register: apt_get_contents

    - name: apt-get clean
      action: command apt-get clean
      when: apt_get_contents.stdout.find("0 upgraded") == -1

TASK: [apt-get clean] *********************************************************

fatal: [192.168.2.2] => error while evaluating conditional: {% if apt_get_contents.stdout.find("0 upgraded") == -1 %} True {% else %} False {% endif %}

FATAL: all hosts have already failed -- aborting
apt: do not consider not-removed and not-upgraded packages as changes.

If one pins a package and does a 'apt-get dist-upgrade' then the
output looks like:

    # apt-get dist-upgrade
    Reading package lists... Done
    Building dependency tree
    Reading state information... Done
    Calculating upgrade... Done
    The following packages have been kept back:
      cassandra
    0 upgraded, 0 newly installed, 0 to remove and 1 not upgraded.

The check for any changes made should only be on the 'upgraded' and
'newly installed' values and not include the 'to remove' and 'not
upgraded' values.
Update cache check in find_plugin

I am not familiar with the internals, but this line looked suspicious.
Restructure the documentation index.
Add new topics to index
Fix index formatting.
Refactor install guide
Add missing file (stub)
Cleaunup to the getting started section.
Clean up inventory section.
Organize dynamic inventory documentation.
The patterns document is now it's own chapter since it applies to playbooks and /usr/bin/ansible alike.
Update the /usr/bin/ansible example docs
Add lots of docs on configuration settings, explaining what goes into ansible.cfg
Refactor the roles information and provide a good example of the case for using roles.
Consolidate docs on accelerated mode
Update check mode docs
Delegation documentation split
Conditionals chapter and some misc tweaks elsewhere
Refactor looping docs