add basic chef-vault topic

because it’s in the chef-dk
Merge pull request #278 from juliandunn/fix-docs-client

Fix missing reboot_pending? in docs_client
clone it
add to index
add link to blog post
Experiment with Travis building
Fix comment
Do the whole thing, see how long it takes
Attempte parallelization of builds to get under 50 minutes
Make Sphinx blow up fatally on nitpicky errors.
Parallelize the build.
Turn off -j4; seems to cause instability