Created snake2Player

-This code being the first multiplayer implementation is rough in terms of organization and optimization but does not have any known bugs (excepting one bug on Windows, addressed below, which will not be fixed).
-This version of the code treats a long side of the LED array as the bottom of the screen. Due to how orientation-independent most of Snake's mechanics are, this would be easy to change later.
-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 bodies of getLeftInput() and getRightInput(). The snakes can then be controlled by WASD and IJKL respectively.
-NOTE: control of player two's snake does not work on Windows because the getLeftInput() call reads and discards all non-WASD input and then getRightInput() is called before another character is entered. The fact that player two's snake does work given proper input can be demonstrated by commenting out the first call of moveHeadCoords() or switching its line with the subsequent one. The final, joystick input will not cause this problem.