networking.md: Networking between containers works without ip_forward

Docker-DCO-1.1-Signed-off-by: Erik Inge Bolsø <knan@redpill-linpro.com> (github: knan-linpro)
Remove redundant checks in runconfig.Merge

Docker-DCO-1.1-Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com> (github: LK4D4)
Cleanup Cmd on ENTRYPOINT instruction

Fixes #5147
Docker-DCO-1.1-Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com> (github: LK4D4)
Inherit Cmd only if no --entrypoint specified on run

Fixes #5147
Docker-DCO-1.1-Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com> (github: LK4D4)
Merge pull request #7349 from knan-linpro/master

networking.md: Networking between containers works without ip_forward
Merge pull request #6909 from LK4D4/prune_cmd_on_entrypoint_setting_#5147

Cleanup cmd on entrypoint setting
Restart containers based on restart policy

Signed-off-by: Michael Crosby <michael@docker.com>
Cleanup restart logic in monitor

Signed-off-by: Michael Crosby <michael@docker.com>
Add typed RestartPolicy

Signed-off-by: Michael Crosby <michael@docker.com>
Refactor container monitor into type

Signed-off-by: Michael Crosby <michael@docker.com>
Add documentation and update restart rules.

Implement time backed backoff for restarting and fix failure count when
the maximum is 0

Signed-off-by: Michael Crosby <michael@docker.com>
Update docs based on feedback from review for --restart