Added intro game state and placeholder assets.

src/gstate.lua

@@ -39,11 +39,20 @@ end
 function GameState:unload()
 end
 
-function GameState:keypressed(_)
+
+function GameState:keypressed(_, _ , _)
 end
 
 
-function GameState:mousemoved(_, _)
+function GameState:textinput(_)
+end
+
+
+function GameState:keyreleased(_, _)
+end
+
+
+function GameState:mousemoved(_, _, _, _)
 end
 
 
@@ -51,6 +60,9 @@ function GameState:mousepressed(_, _, _)
 end
 
 
+function GameState:mousereleased(_, _, _)
+end
+
 ------------------------------------------------------------------------------
 -- Module return
 ------------------------------------------------------------------------------