Lots of new documentation

Just wrote and pushed a lot of documentation, mostly for features in
1.1 (and are

Environment variables and proxies:
http://ansible.cc/docs/playbooks2.html#setting-the-environment-and-working-with-proxies

--check-mode (dry run):
http://ansible.cc/docs/playbooks2.html#check-mode-dry-run-check

--diff:
http://ansible.cc/docs/playbooks2.html#showing-differences-with-diff

Complex arguments and how to use them:
http://ansible.cc/docs/playbooks2.html#passing-complex-arguments-from-dictionaries

Ability to pass nested variables to task includes
http://ansible.cc/docs/playbooks2.html#advanced-task-includes
http://ansible.cc/docs/playbooks.html#task-include-files-and-encouraging-reuse

Best Practices Overhauled:
http://ansible.cc/docs/bestpractices.html

In addition, I've also organized the 1.1 changelog for those who want
to keep up with what we have added so and done so far:

https://github.com/ansible/ansible/blob/devel/CHANGELOG.md

So far 1.1 contains already more than what was in 1.0, and this is
less than halfway into the release. So a lot of stuff there!

--Michael