Many changes all around. Started main menu.

Added Drawable, Sprite and SoundEffect classes.
Added comments to Fader class.

src/ui/sprite.lua

@@ -0,0 +1,48 @@
+------------------------------------------------------------------------------
+-- Imports
+------------------------------------------------------------------------------
+
+local love       = require 'love'
+local make_class = require 'src.utils.classes'
+local Drawable   = require 'src.ui.drawable'
+
+------------------------------------------------------------------------------
+-- Class definitions
+------------------------------------------------------------------------------
+
+local Sprite = make_class(Drawable)
+
+
+------------------------------------------------------------------------------
+-- Class methods
+------------------------------------------------------------------------------
+
+function Sprite:_init(sprite_name, x, y)
+    self.sprite_name = sprite_name
+    self.x = (x ~= nil and x) or 0
+    self.y = (y ~= nil and y) or 0
+end
+
+
+function Sprite:load()
+    self.sprite = love.graphics.newImage(self.sprite_name)
+end
+
+
+function Sprite:draw()
+    if self.sprite ~= nil then
+        love.graphics.draw(self.sprite, self.x, self.y)
+    end
+end
+
+
+function Sprite:unload()
+    self.sprite = nil
+end
+
+
+------------------------------------------------------------------------------
+-- Module return
+------------------------------------------------------------------------------
+
+return Sprite