Allow inventory scripts to define groups of groups and group vars

Fix pip module to check if requirements already installed

This updates _is_package_installed() to accept a requirements file
as an argument.  This is used later in main() to check if python libs
specified in a requirements file are already installed.  I updated
main() to consolidate the handling of install/uninstall in a single
block.  This should help if someone wants to remove packages specified
by a requirements file.

Updated ansible version to align with RPM package

check path is directory
added manpage & setup
small cleanup
shut up module_formatter in utils to avoid trace print on crud files in library

Fixes the case where a handler attempts to run for every batch after any
batch has notified it, regardless of whether the current batch did.

This ensures we don't litter remote systems with temporary directories
that don't get cleaned up, as well as speeds things up from not having
to touch every node.

Skip already failed hosts for serial

Fix subversion module's documentation

Let our users determine what they want to do with a given module.
Particularily when the mdoule doesn't pose any such restrictions.

Fixes #1699.

Broken by 1e0295c7. Fixes #1698.

dpkg -l does not install package, use dpkg -i <package-file> instead

This reduces the amount of times an inventory script has to be invoked.

ini_file: prohibit section name 'default'

Set LANG in module_common.py

allow update of default section
add blurb re template to create base file

Add constant DEFAULT_MODULE_LANG that defaults to C.  Can be set via
environment variable ANSIBLE_MODULE_LANG or configuration variable
module_lang.  Updated test-module to have same behavior.

This allows overriding variables in name, and removes templating from
parsing.

Fixes #1622.

Fixes #1677.