Mention the integrated terminal in readme

[paulirish]

(especially since it's the only reason we have this compilation step)

We could also add a new screenshot for that, too

[rainabba]

Where do I learn more about that integrated terminal in the meantime?

[DrewML]

@rainabba It's in the bottom of the debugger, in a tab next to the console:

[rainabba]

Thanks for clarifying. I look forward to checking it out once I can get ndb running on WSL :/

[sheerun]

It's not really clear or documented that you need to press Esc to show this terminal