Added assets manager singleton.

src/gstates/gstate.lua

@@ -3,8 +3,10 @@
 ------------------------------------------------------------------------------
 
 local make_class = require 'src.utils.classes'
+local assets     = require 'src.utils.asstmngr'
 local Drawable   = require 'src.graphics.drawable'
 
+
 ------------------------------------------------------------------------------
 -- Class definitions
 ------------------------------------------------------------------------------
@@ -18,8 +20,8 @@ local GameState = make_class(Drawable)
 
 function GameState:_init(name, index)
     Drawable._init(self)
-    self.name  = name
-    self.index = index
+    self.name   = name
+    self.index  = index
 end
 
 
@@ -28,6 +30,15 @@ function GameState:update(_)
 end
 
 
+function GameState:load()
+end
+
+
+function GameState:unload()
+    assets:unload(self.name)
+end
+
+
 ------------------------------------------------------------------------------
 -- Module return
 ------------------------------------------------------------------------------