Add the ToDo's we need to do to release the game

doc/TODO

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+Initial release
+
+## GFX
+* Title Screen
+* Main background screen
+* Ball
+* Game over screen
+* Highscore-Screen
+* Font for score
+
+## Sound
+* Background-tune?
+
+## Code
+* Pause-Mode (pause the game)
+* Improve the AI intelligence (more randomness)
+* An special effect on ball hit (sprite/glor/whatever)
+* "pulse" paddle on hit
+* Highscore-Script (PHP, and a mechanism to not fake the score)
+* Display the Highscore in the game
+* Put the Player (with name) on the highscore