Documentation Clean up

I made a few updates to the documentation that you may appreciate. I'll try to list out the changes within:
- some very small typos (seemingly caused by English being your second language :smile:)
- added two badges - dependencies & npm module
- converted the markdown heading hierarchy to use the ### syntax, which is a bit more intuitive in my opinion
- changed references of "liquor" to "beverage" which I think you were confusing with "liquid". But "beverage" might be more suitable 
- a little bit of separation between prompt types using the horizontal rule to make it more readable 

In any case, inquirer.js is great! We're using it to great success on [carrot/sprout](https://github.com/carrot/sprout) and wanted to contribute back in even a small way.