Make it possible to disable TLS, and add some reluctant documentation for it

Closes #571

Signed-off-by: Sven Dowideit <SvenDowideit@docker.com>
Merge pull request #572 from SvenDowideit/allow-tls-disable

Make it possible to disable TLS, and add some reluctant documentation for it
add 'recommend' to make sentence make sense

+formatting to keep lines consistent length
Merge pull request #592 from cglewis/master

add 'recommend' to make sentence make sense