Add a yaml format inventory plugin.

Openstack rackspace update

Module network_facts to gather facts based on network information

Typo in example section for 'setup' module docs.

This fixes #1265.

Sigh, another retypo

Fixes to documentation

Makes ports configurable for fireball.  Note port defaults really belong in the connection plugins, not runner, which can be refactored later.

Various small fixes to boolean usage and defaults

cron feature (w/o tests)

Keep the man3 directory. 'make docs' breaks without it.

Add this module's namespace to the 'module_' namespace.

Fix typo in service module docs

Add inventory variables for hosts not in the play to hostvars.

Look up only when requested and cache the result.

Much like we currently have *setup* register the variable `module_setup`, we would like other facts-modules register their own namespace. This means that:

 - *network_facts* registers `module_network`
 - *hpilo_facts* registers `module_hw`
 - *vsphere_facts* registers `module_hw`

In retrospect, it would have made more sense to have `setup` register `module_ansible` instead as the setup module uses the `ansible_` namesepace.

Having the `module_` namespace allows us to check whether a certain namespace has already been loaded so we can avoid running the facts module a second time using only_if.

```yaml
 - action: network_facts host=${ansible_hostname_short}
   only_if: is_unset('$module_network')
```

chapter 3 manpage source does not belong in git because it includes datestamps that constantly change.  Willing to re-add if datestamps
are removable.