collision detection: improved readability
shorter movement notation
DRY: implemented paint_rect function
created canvas class for drawing
include compiled js files
changed folder structure
implemented game loop with requestAnimationFrame
implemented snake class
added delta time to loop callbacks
added snake speed logic
removed function wrapper in main.js
added core game class
moved requestAnimationFrame polyfill to separate file
added food class
added render methods to food and snake
moved snake update logic to snake class
implemented game loop in game core class