Renamed docker binary to mitigate conflict with docker CLI

[reiner-dolp]

If you are using docker.js with npm you can get around this issue by executing docker through package.json scripts:

1. Install docker.js locally in your project, e.g. as dev dependency.
2. Run docker.js as a npm script: npm run generate-docs

Minimal package.json example:

{
    "devDependencies": {
        "docker": "0.2.14"
    },
    "scripts": {
        "generate-docs": "docker /* your args */"
    }
}

docker will reference the "container-manager" in your shell, and docker.js in npm scripts.