ADDED COMMENTS. I STILL HAVE MORE HOMEWORK TO DO TOMORROW. AH. BYE.
Got tab completely working.  Not only does tabbing when nothing is there now return nothing and do nothing (yay), tabbing when there are multiple options will show the options, advance to the next line, put the prompt, and also put the letter that was originally typed, allowing the user to see the suggestions and then type the rest of the word.  Fawk yeah.
Fixed scroll so that it makes no sense anymore.  This is the kind of scrolling that Sean Connery would write.
Added some comments because comments are super importante.