Don't exit on eof in header reading in stdcopy

There was random lines drops in docker logs because of this
Docker-DCO-1.1-Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com> (github: LK4D4)
Increase time before exit in TestMultipleAttachRestart

Sometimes third attacher attaching to already stopped container.
Also I've changed prefix to attach and fixed cleanup on Fatal.
Docker-DCO-1.1-Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com> (github: LK4D4)
Convert TestGetContainersByName into a unit test

Docker-DCO-1.1-Signed-off-by: Guilherme Salgado <gsalgado@gmail.com> (github: gsalgado)
Move TestBuildEntrypointRunCleanup to integration-cli

Docker-DCO-1.1-Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com> (github: LK4D4)
Move TestForbiddenContextPath to integration-cli

Docker-DCO-1.1-Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com> (github: LK4D4)
Move TestBuildADDFileNotFound to integration-cli

Docker-DCO-1.1-Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com> (github: LK4D4)
Move TestBuildInheritance to integration-cli

Docker-DCO-1.1-Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com> (github: LK4D4)
Move TestBuildFails to integration-cli

Docker-DCO-1.1-Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com> (github: LK4D4)
Move TestBuildFailsDockerfileEmpty to integration-cli

Docker-DCO-1.1-Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com> (github: LK4D4)
Move TestBuildOnBuildTrigger to integration-cli

Docker-DCO-1.1-Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com> (github: LK4D4)
Move TestBuildOnBuildForbiddenChainedTrigger to integration-cli

Docker-DCO-1.1-Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com> (github: LK4D4)
Move TestBuildOnBuildForbiddenFromTrigger to integration-cli

Docker-DCO-1.1-Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com> (github: LK4D4)
Move TestBuildOnBuildForbiddenMaintainerTrigger to integration-cli

Docker-DCO-1.1-Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com> (github: LK4D4)
fixed a broken link in the docs
Docker-DCO-1.1-Signed-off-by: Matt Williams <lp@mattyw.net> (github: mattyw)
Merge pull request #6356 from mattyw/master

fixed a broken link in the readme
Move TestBuildAddToSymlinkDest to integration-cli

Docker-DCO-1.1-Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com> (github: LK4D4)
Refactor events publishing

Events subscription (/events API endpoint) attributes pseudo-unique identifiers to incoming subscribers: originally its host, then its subscription time. This is unecessary and leads to code complexity.

Introduce a JSONMessagePublisher to provide simple pub/sub mechanism for JSONMessage, and rely on this new type to publish events to all subscribed listeners. The original logic is kept for the 'since' and 'until' parameters, and for client disconnection handling.

Docker-DCO-1.1-Signed-off-by: Arnaud Porterie <icecrime@gmail.com> (github: icecrime)
Update libcontainer dependency to 77ffd49dfedbc78a

Fixes #6256
Fixes #6383
Fixes #6414

Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@docker.com> (github: crosbymichael)
prevent panic when empty flag

Docker-DCO-1.1-Signed-off-by: Victor Vieux <vieux@docker.com> (github: vieux)
Merge pull request #6471 from LK4D4/more_buildfile_tests_to_cli

Move more buildfile tests to integration-cli