remove loop in favor of blocking io

This modification prevents ruby apps from consuming 100% of a single CPU core's processing power, but Kristen claims that this approach runs into issues. Can we identify what those issues might be, and if possible pull this commit?

### Why Ruby was using all of the CPU power:

The following code appears in `lib/mycroft/client.rb`:

```ruby
loop do
  if @client.ready?
    size = @client.readline
    ...
    end
  end
  ...
end
```

Note that `@client.ready?` will return `false` until the client has data ready to consume. Consequently the code shown above will form an infinite loop, using up all CPU available.