Lunchbox CLI Interface!

This update wraps the existing functionality in a nice CLI interface.

Notable changes:
- Instead of simply running 'lunchbox' to execute the script - the user is now required to run `lunchbox run`
- Running `lunchbox self-update` will cause Lunchbox to update its self with the latest version found in bigspring/lunchbox
- Various README changes to reflect and document the above change in functionality
- Bumped version to v1.1.0

Note: I got a little trigger happy and already set the 'self-update' repo to bigspring/lunchbox (see https://github.com/martindines/lunchbox/blob/master/lunchbox#L34) So running self-update will not have an effect unless these set of changes are merged in to master.