Update RELEASE-CHECKLIST to mention how to get a decent contributors list

Docker-DCO-1.1-Signed-off-by: Andrew Page <admwiggin@gmail.com> (github: tianon)
Fixes headings in Table of Contents, link from FAQ.
Docker-DCO-1.1-Signed-off-by: Andy Rothfusz <github@developersupport.net> (github: metalivedev)
mac-installation-docs: Update the installation dir.
Docker-DCO-1.1-Signed-off-by: O.S. Tezer <ostezer@gmail.com> (github: ostezer)
Merge pull request #3927 from tianon/release-checklist-mention-contributors

Update RELEASE-CHECKLIST to mention how to get a decent contributors list
Merge pull request #3929 from ostezer/master

mac-installation-docs: Update the installation dir.
Merge pull request #3928 from metalivedev/fixheadings

Fixes headings in Table of Contents, link from FAQ.