Add up, down commands for starting and stopping agents specified in local Lunchyfile

The enclosed commit provides a solution to issue #10. The <code>Lunchyfile</code> simply contains a list of agents or agent patterns. It can also contain comments (preceded by pound sign). Here's an example:

    # NoSQL databases
    mongo
    redis

    # PostgreSQL
    postgres

The command <code>lunchy up</code> starts all agents specified in the <code>Lunchyfile</code>.
The command <code>lunchy down</code> stops all agents specified in the <code>Lunchyfile</code>.