New ansible-examples content merged recently

Hi everyone,

I spent some time this week writing and merging some new example
content into our ansible-examples respository:

https://github.com/ansible/ansible-examples

Thanks to a few contributors (Dave Johnson and Benno Joy from
AnsibleWorks, and James Martin from Riak) we are now up to 10
examples. The new ones include:

- jboss-standalone: a simple JBoss AS 7 deployment, just the app
server running standalone, from Dave J.
- tomcat-standalone: very similar to the JBoss example.
- riak: production-ready Riak playbooks from Basho
- hadoop: CDH4 deployment playbooks from Benno Joy
- play: A Scala-based "Play" webapp from Benno Joy
- wordpress-nginx: Wordpress+Nginx+PHP-FPM+MySQL, from yours truly.

Several of these have an "Ideas for Improvement" section in the
README. If you're interested in contributing to this project, please
have a look through and see if there's a todo item you'd like to
tackle! Or if you'd like to contribute an entire new project, please
send a PR!

Thanks, and I hope people find this useful!

-Tim