Added documentation for docker.io OAuth & Accounts

OAuth docs:
  documented the OAuth authorization flow and how to register your application

Account docs:
  documented getting/updating user profile data
  documented getting/updating user email data

Docker-DCO-1.1-Signed-off-by: Josh hawn <josh.hawn@docker.com> (github: jlhawn)
Updated OAuth docs per arothfusz's comments

Added emphasis of https for OAuth interactions.
Updated example URIs to use HTTPS
Included redirect hostname on authorization page.

Docker-DCO-1.1-Signed-off-by: Josh hawn <josh.hawn@docker.com> (github: jlhawn)
fix EventsListeners in docker info

Docker-DCO-1.1-Signed-off-by: Victor Vieux <victor.vieux@docker.com> (github: vieux)
one ponted out by lukaspustina, and one that I bet I added

Docker-DCO-1.1-Signed-off-by: Sven Dowideit <SvenDowideit@fosiki.com> (github: SvenDowideit)
Merge pull request #4319 from jlhawn/docs-docker-io-api

Added documentation for docker.io OAuth & Accounts
Merge pull request #4390 from SvenDowideit/spelling-1

one ponted out by lukaspustina, and one that I bet I added
Merge pull request #4388 from vieux/fix_eventlisteners_nb

fix EventsListeners in docker info
Check if the command exists before dereference

Docker-DCO-1.1-Signed-off-by: Guillaume J. Charmes <guillaume.charmes@docker.com> (github: creack)
Merge pull request #4394 from creack/fix_tty_ghost

Check if the command exists before dereference