Add submodules for new core and extras subdirectories of modules, not yet live.
Modules is a package.
Update module test code to avoid pycs (that are not used)
changes for package loading of modules
Updating the module formatter to deal with the new repo structure.
Some various comments about the new repos, more to likely come.
README update
hacking/env-setup no longer needs to set library since modules appear as git submodules.
Removing legacy test dir
Docsite formatting
Add a new inventory parameter (ansible_sudo_exe) to specify sudo command path.
Updated installation instructions for submodules

Added `--init --recursive` to installation instructions
as per @bcoca's suggestion on ansible-project mailing list
Update README.md
Doc fix in intro_installation.rst

Missing code block
Update intro_configuration.rst
Fix link in reST template

There was a missing trailing underscore (`_`) that would have marked the
content in the backticks as a link. This adds it and fixes the link on
every core module page.
Merge pull request #9185 from willthames/submodule_install_docs

Updated installation instructions for submodules
Updated version info to include submodule information

`ansible --version` etc. now include information about submodules

```
ansible 1.8 (submodule_ansible_version ffee9a8fe0) last updated 2014/09/28 11:03:14 (GMT +1000)
  lib/ansible/modules/core: (ec2_snapshot_remove 3a77c31ecb) last updated 2014/09/27 18:23:31 (GMT +1000)
  lib/ansible/modules/extras: (detached HEAD 110250d344) last updated 2014/09/27 14:33:42 (GMT +1000)
```

Also improved handling of detached HEAD when printing out version
information.
Cater for uninitialized submodules

Output a useful message if `git submodule update --init --recursive` not
yet performed

```
$ ansible --version
ansible 1.8 (submodule_ansible_version 59ae596484) last updated 2014/09/28 13:20:51 (GMT +1000)
  lib/ansible/modules/core: (detached HEAD 617a52b20d) last updated 2014/09/28 13:15:25 (GMT +1000)
  lib/ansible/modules/extras:  not found - use git submodule update --init lib/ansible/modules/extras
```
If submodules are not found, don't error out.