It's a common pattern for command line tools to have multiple subcommands, this
patch implements a new subcommand command line interface. Each subcommand has
its own set of required and optional parameters.

The current implemented subcommands are:

    submit     Submit job files
    cancel     Cancel job files
    resubmit   Resubmit job files
    results    Fetch job id list results

See 'lqa <command> -h' to read about a specific subcommand.

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>