Add a plugin that permit to use ansible for lxc system, using libvirt

Using -c lxc and the domain name as hostname, this permit to manage a whole
range of container, provided they are managed and created by libvirtd.
add a inventory script that go with the lxc connexion module
[digital_ocean] Don't die when the id parameter is missing

It's okay for this to happen now, because we might move on to the name parameter
if unique_name is enabled.
Add basic domain handling to digital_ocean cloud action
[digital_ocean] revert original module and add one new module for each command
[digital_ocean] Remove command usage from digital_ocean_ssh examples

I seem to have forgotten to do this in my last commit.
Add packaging module for Gentoo Portage.

This is in no way comprehensive enough to cover all use cases, but hopefully
is sufficient to cover the common ones.
Added metadata support to s3 module
Additional idempotent states for virt module: "destroyed" and "paused"
Rename digital_ocean_ssh to digital_ocean_sshkey per https://github.com/ansible/ansible/pull/4315#issuecomment-30286556
allow per-host sudo operation
Basic handling of locales.
Handle install/uninstall of locales for Ubuntu, too.
Merge remote-tracking branch 'upstream/devel' into locale
Fix error reporting in case locale-gen fails on non-Ubuntu systems.
Add support for string values

The SET GLOBAL statement requires properly quoting of values. For example, the
following correct queries will fail if quotes are toggled:

mysql> SET GLOBAL innodb_lru_scan_depth = 2000;
mysql> SET GLOBAL master_info_repository = "TABLE";

`mysql_variable` module doesn't quote the value argument, therefore
string values will fail.

  # this task will pass, 2000 is passed without quotes
  - name: set a numeric value
    mysql_variable: variable=innodb_lru_scan_depth value=2000

  # this task will fail, TABLE is passed without quotes
  - name: set a string value
    mysql_variable: variable=master_info_repository value=TABLE

With this patch prepared statements are used. Proper quoting will be
done automatically based on the type of the variables thus an attempt
to convert to int, then to float is done in first place.

Booleans values, ie: ON, OFF, are not specially handled because they
can be quoted. For example, the following queries are correct and
equivalent, they all set _innodb_file_per_table_ to logical _True_:

mysql> SET GLOBAL innodb_file_per_table = "ON";
mysql> SET GLOBAL innodb_file_per_table = ON;
mysql> SET GLOBAL innodb_file_per_table = 1;

Tested in mysql 5.5 and 5.6.
Updated S3 metadata examples
Refactored a few things to be more inline with the Ansible way. Passing testing.
Documentation cleanup.
Cleaning up pep8 alerts.