Tests for starting a Container with existing configuration

This illustrates an issue with current docker-java: you cannot send a
StartContainerCmd without payload.
Do not serialize unconfigured values in StartContainerCmd

Any payload sent with the StartContainerCmd will cause the target
container to lose its customization.
So in order to just start a preconfigured container you must be able to
send an empty "{}" message to the /containers/{id}/start endpoint.

This is accomplished by all configuration defaulting to null in
combination with @JsonInclude(NON_EMPTY).
Update README.md
Update README.md
Merge pull request #111 from albers/empty-start-command

Allow to send empty messages in StartContainerCmd
Update CHANGELOG.md
Update CHANGELOG.md
Update CHANGELOG.md
Test for serialization of an unconfigured StartContainerCmd,
documentation
Merge pull request #112 from albers/empty-start-command

Test for serialization of an unconfigured StartContainerCmd
Test for StartContainerCmd.withVolumesFrom()
Fix CreateContainerCmdImpl.withVolumesFrom()

Another method that did not work until Docker Remote API 1.15, see
CreateContainerCmd.withDns().

To fix it, the parameter had to be moved to nested HostConfig.
Change serialization of RestartPolicy.noRestart()

The Docker CLI uses "" as the name for the --restart no policy.
Parser and toString for RestartPolicy
Merge pull request #114 from albers/fix-create-withVolumesFrom

Fix CreateContainerCmdImpl.withVolumesFrom()
Merge pull request #115 from albers/restart-policy

Polish RestartPolicy
Update CHANGELOG.md
Use chunked encoding when passing the docker image.

If you don't do this, you very often run out of heap space, as the
webclient will create a buffer for the entire image file (possibly
many gigabytes) before sending it.

Signed-off-by: Nigel Magnay <nigel.magnay@gmail.com>
Merge pull request #118 from magnayn/pr2

Use chunked encoding when passing the docker image.
Update CHANGELOG.md