Edit gates.txt for clarity
Printing the graphic is now centered in the terminal
Create ASCII art for gates level
Move all gate graphic functionality to display
* display deals with messy ASCII art
Move gates display function down and label section
Extract centering functionality to new method
* add newline after final "wall" section of graphic
Rename print_text to emphasize dealing with a file
Game asks user to pick a lever
* new interface function int_input() parses integers