TowerDefenseMenuVersion1.03

Includes game over menu. When the HP reaches 0 a game over menu pops up. In the game over menu, there's a restart text where if you click it, it'll restart the previous level. There's also a Return to Main Menu text where if you click it, it'll return you to the main menu. Also changes are made to the game menu script. Instead of using if(MouseButtonPress) I used void OnMouseDown() methods. Also gold is no longer int, it is now float.

Corresponds to: User should be able to see a game over screen when he runs out of lives.