WASD and arrow keys both control movement.

Space and shift move the player up and down, respectively.

Z switches between shaders (and one option which indicates no shader, i.e. the built-in pipeline). The current list of
shaders is None, Simple, Phong, and a simple cell-shader, in that order.
The Phong shader also implements normal mapping on the terrain.

C toggles the day/night cycle (the cycle is 1 minute long, with shifting colors).

L toggles the flashlight. When using shaders, the normal cosine cutoff isn't implemented because it looks ugly as hell.

Since I use key bindings (KeyEventListeners are apparently considered deprecated), the frame/panel will sometimes
lose focus upon creation. I've done my best to automatically get focus upon creation, but if it loses it, it seems
the only solution is to re-run the program. Apologies to the marker :(