zabbix_group: new module

Add or remove a host group to Zabbix.

Signed-off-by: René Moser <mail@renemoser.net>
New crypttab module for editing Linux /etc/crypttab file
rename list to list_ to avoid shadowing in github_hooks module

The definition was leaking into ansible.module_utils.basic and causing
type checking to fail when running module as script.  Not entirely clear
why this should be the case.
make it possible to configure the content type of a github webhook
pvs args shall be submitted as a list

pvs args are submitted as a string to vgcreate, but the run_command
expects a list however. This caused problem for multiple args.
Add bower module
Module alternatives: support check mode
Module alternatives: support RedHat-based OSes

RedHat-based OSes have a version of update-alternatives which comes from
the chkconfig package and does not support the --query parameter. Work
around that.
Add module to install windows updates

Supports specifying which category to install all updates from.
NEEDS: `choco install PSWindowsUpdate` beforehand - does not attempt to install it (or detect it's missing, yet)
PSWindowsUpdate: http://gallery.technet.microsoft.com/scriptcenter/2d191bcd-3308-4edd-9de2-88dff796b0bc#content
Added module haproxy, to handle enable/disable backend server with shutdown_sessions feature in haproxy.
mark list as private instead of shadowing
mark all actions as private
Created dnf package manager module, based on the yum package manager module.
Windows package management with Chocolatey
Added GlusterFS module.
corrected and made better docs for getent
Fixed cachedir function
Added .py extension to glusterfs module.
Snmp module for Ansible
Update the webhook url

This change fixes the 404 seen with the current version.

fixes #100