Added services listing command

# Use Case
I was integrating fig into our existing puppet infrastructure and decided I wanted to control scaling, but have no nice way to list the current scale count for ensuring each service has the correct count... Also this command makes me happier when dealing with services inside a project.

# Usage
    List services
        Usage: services [options] [SERVICE...]
        Options:
            --ps    List state information like ps for each service

Signed-off-by: Nick Shobe <nickshobe@gmail.com>