Ok, some major changes. UI is finished. It is also now the top tier (it
instantiates Game Engine, which instantiates everything else). Some
minor changes to Game Engine (mostly in its reactions with UI), also
decided to make the user input a series of specific strings. We can use
the .equalsIgnoreCase() method for our if-else statements and it will
make the program more user friendly. Finally, I got distracted and wrote
a lot of the code for Grid.. so whoever's that class was, sorry about
that. But we should be all good to go with our skeleton code.