Move volumes out of container.go and into volumes.go

This helps clean up the container file and move volumes into
one location.  We currently cannot move volumes to a sub pkg
because they depend on Container and also modify fields on the
container.
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Remove container dependency for links
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Move links to sub pkg
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Merge pull request #4162 from crosbymichael/movelinks

Move links functionality into pkg
Merge pull request #4159 from crosbymichael/move-volumes

Move volumes out of container.go and into volumes.go
Fix remote tar ADD behavior

Docker-DCO-1.1-Signed-off-by: Guillaume J. Charmes <guillaume.charmes@docker.com> (github: creack)
Merge pull request #4193 from creack/3964-add_tar-fix

Fix remote tar ADD behavior
Rewrite docker rmi

Docker-DCO-1.1-Signed-off-by: Victor Vieux <victor.vieux@docker.com> (github: vieux)
bump API version

Docker-DCO-1.1-Signed-off-by: Victor Vieux <victor.vieux@docker.com> (github: vieux)
:= / var

Docker-DCO-1.1-Signed-off-by: Victor Vieux <victor.vieux@docker.com> (github: vieux)
fix tests

Docker-DCO-1.1-Signed-off-by: Victor Vieux <victor.vieux@docker.com> (github: vieux)