Implemented "garbage lines" and checkerboard tiles

Changes:
-Added the ability to add "garbage lines" to shorten the playfield over time, forcing the game to end faster. Example calls to the addGarbage function are commented in the code where they might appear. The most likely way we might trigger the function is based on time elapsed since the start of the game.
-Added drawCheckerboard, which functions similarly to drawRectangle but is visually distinct. This is used for the borders and garbage lines.
-Removed a depreciated and unused getRightInput definition.

Notices: (*changed from last commit*)
-This version of the code treats a long side of the LED array as the bottom of the screen. This may not be the case for the final single-player version of Tetris, but it makes testing the code easier.
-This version of the code includes a global 3D array to temporarily skirt the development complications of a planned tetrominoes.h, which would just include that 3D array.
-This version of the code includes a placeholder menu. It also includes test input handling for Windows, which can be enabled in Windows by de-commenting everything below the two "/*Windows:*/" tags and commenting everything below the "/*Linux:*/" tags, as well as de-commenting the body of getLeftInput(). The keybindings are as follows:
A - shift left
D - shift right
S - "soft drop" (shift one space downward)
W - "hard drop" (shift all the way downward and spawn a new piece)
Q - spin counter-clockwise
E - spin clockwise

To do:
-Clean up the code in general.
-Create piece shadow functionality. It may be to visually cluttering, or even inefficient, to have the a copy of the active piece displayed as low as the active piece can go in its current orientation, but it could just as easily be critical.
-Consider options for displaying the next piece(s) and the held piece, if such functionality is desired. The code for handling this data would be quite simple to write, but the code to display the information would be dependent on screen size and layout. Not a priority.