Add a timeout decorator for timing out functions that may hang

Fixes #6891
Make test-module interpret --args='{...' as yaml
Explain how to do multiple paths in roles_path

Document that roles_path can support multiple colon-separated paths
What particular script?

Moved a sentence. Sentence refers to script, "this particular script" before it has been introduced. Moved sentence to after intro as it confused me. I though I'd missed something..
Added example demonstrating other functionality
fix typo
docker: from API 1.10 dns and volumes_from should be passed to start()
cloud/elasticache: Ensure self.data is iterable

- self.data['SecurityGroups'] can return None causing traceback, if that
  is the case fallback to an empty list
Fix empty group in rax.py output
Add reference to the join filter.
Fix typos in ansible-playbook man page source

Note: the man page needs to be rebuilt.
Merge pull request #6971 from ciupicri/fix-manpage

Fix typos in ansible-playbook man page source
Merge pull request #6970 from nZac/doc-jinja-join-filter

Add reference to the join filter.
Merge pull request #6969 from sivel/rax-inventory-fix-empty-group

Fix empty group name in rax.py output
Merge pull request #6965 from mjschultz/fix-6964

cloud/elasticache: Ensure self.data is iterable
Merge pull request #6956 from mattjbray/docker-1-10-volumes-from-dns

docker: from API 1.10 dns and volumes_from should be passed to start()
Merge pull request #6954 from rasputnik/patch-1

fix typo
Merge pull request #6952 from nousdefions/devel

Added example demonstrating other functionality
Merge pull request #6950 from sam-at-github/patch-1

What particular script?
Merge pull request #6944 from ex-nerd/patch-1

Explain how to do multiple paths in roles_path