Allow parameterized playbook includes to define complex variables

To be used like:
- include: playbook.yml
  vars:
    mylistvar:
    - item1
    - item2

Change message when a play matches no hosts

change error message on check_conditional when variable does not exist

Make use of yes/no booleans in playbooks

fixes #1767 parsing serial from extra_vars

fix and clarify 'script' docs

Fix hostname expansion bug in inventory parser

cleanup Example output in ansible-doc

At the moment Ansible prefers yes/no for module booleans, however booleans in playbooks are still using True/False, rather than yes/no. This changes modifies boolean uses in playbooks (and man pages) to favor yes/no rather than True/False.

This change includes:

- Adaptation of documentation and examples to favor yes/no
- Modification to manpage output to favor yes/no (the docsite output already favors yes/no)

Ensure files created by authorized_key have correct selinux context

Three changes:
* Add set_default_selinux_context() to module_common that sets
  a file's context according to the defaults in the policy
* In atomic_replace(), set the default context for the file if
  selinux is enabled and the destination file does not exist.
* In authorized_key, set the default context when creating
  $HOME/.ssh and $HOME/.ssh/authorized_keys.  If these already
  exist, this won't touch them.

Missing colon in $FILE example docs

Subverion module improvements

I guess my previous pull request was confusing, by changing the message to something we already do for tasks, it makes it more clear.

Just like we say:

    TASK: [foo bar]
    skipping: [system01]

The message now is more clear:

    PLAY [wagawaga] *******************************
    skipping: no hosts matched

It makes it clear that we are skipping the play, just as is done for a task when a condition is not met.

mail module: add MIME attachments, port and addresses with phrases

add list-hosts support to bin/ansible

Allow regex to be used to select hosts in addition to fnmatch pattern

Allow intersecting host patterns by using &

Fix ppa syntax in apt_repository module doc

ansible-doc: print Notes heading only if there are any

pip module improvements

Tweak docs for correct paths and filenames for ec2 inventory

- Do not silently ignore malformed pip requirements files.
- Properly reports changed when removing packages.
- "latest" i.e. --upgrade is *not* incompatible with requirements files.
- Less branchy, simpler logic.
- Removed pointless variable "initializations", Python doesn't need that.
  Other code simplifications.
- Fun fact; pip install is (kind of) case insensitive, pip freeze is not.
  So, 'sqlalchemy' will be reported as installed by install, but missing
  by freeze.

The perhaps controversial change and the one that led to finding /
fixing above issues...

Instead of adding command parameters 'index', and 'find', and 'mirrors',
and etc.  Added 'extra_args' which are passed onto pip.

The use case for --index-url is having a private pypi repo, like
http://pypi.python.org/pypi/localshop, to which you publish private
packages.  I'm sure most every pip option has a use case for someone.
extra_args handles all those. Can reserve ansible command parameters for
the most common.

Tested with pip 1.1.

if user has manually installed an intermediate version - don't ignore it...

This allows patterns such as webservers:!debian:&datacenter1 to target
hosts in the webservers group, that are not in the debian group, but are
in the datacenter1 group. It also parses patterns left to right.

make --list-hosts expand out extra vars in the hosts: field

 Add HTML-escaping to code examples in rST tempate of module-formatter
 Add support for specifying port, addresses with phrases and attaching files
 Add support for custom headers and document version_added for new options
 X-Mailer header added :)
 protect empty address lists & attachment list, and add bcc

The example for using a ppa had the wrong syntax.

Ironically, the correct syntax is illustrated in a comment on line 23.