Always terminate upon "nothing"

[kbuffardi]

Currently, the application still responds with a validating message even after the user enters nothing. We need to update the application's behavior so that:

1. When the user enters nothing then it will not respond with a validating message, it will just end the application.
2. Extend the above rule to also apply to the first user input. Currently, nothing only terminates the program when the user enters it in response to the What's next? prompt, but we want it to also behave the same for the initial What are you listening to? prompt.

Example 1:

What are you listening to?
nothing

Example 2:

What are you listening to?
Not Like Us
Perfect! Let's listen to more
What's next?
nothing