Add support for 'commit --change'

The spec for `commit --change` can be found at  https://github.com/docker/docker/pull/5105
This PR changes the original pull request to use new builder for generating `runconfig.Config`

Supported Dockerfile instructions for `--change` are:
```
- ENTRYPOINT
- CMD
- USER
- WORKDIR
- ENV
- VOLUME
- EXPOSE
- ONBUILD
```

Example command:
```
> docker run --name test busybox true
> docker commit --change "EXPOSE 8080 3000" --change "ENV DEBUG true" --change "VOLUME /test1 /test2" --change "WORKDIR /test1" test test-commit
> docker inspect test-commit
"Config": {
  "Env": [
    "DEBUG=true",
    "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
  ],
  "ExposedPorts": {
    "3000/tcp": {},
    "8080/tcp": {}
  },
  "Volumes": {
    "/test1": {},
    "/test2": {}
  },
  "WorkingDir": "/test1"
},
```