use minifb for rendering

src/main.rs

@@ -1,6 +1,3 @@
-// extern crate piston_window;
-// use piston_window::*;
-
 extern crate minifb;
 use minifb::{Key, Window, WindowOptions};
 
@@ -40,8 +37,9 @@ fn main() {
     engine.load_level(level);
 
     while window.is_open() && !window.is_key_down(Key::Escape) {
+        // Reset framebuffer
         for i in buffer.iter_mut() {
-            *i = 0; // write something more funny here!
+            *i = 0;
         }
 
         // if let Some(Button::Keyboard(key)) = event.press_args() {