Updated PvZ skin to have sound effects. Needs other sounds. WIP.
Added the use of whack sound as backup for backward compatibility.
Added sound effect for failure that does not caused by hitting the wall or obstacle.
Rolled back the second to the last commit, as the fallback for audio checks only works with audio types.
Moved the start sound to whenever the execute is called.
Updated pvz sounds and added the birds sounds.
Updated the angry bird success sound with the explosion of the bird.
Added the explosion for obstacles.
Updated the background and tileset for angry birds.
Added the animation when reaching the goal (angry birds).
Pegman disappears when it steps into an obstacle, and becomes visible again when hitting reset.
Added place holders for animation (obstacle and goal). Adjusted the obstacle and goal position.
Updated level 2_4 so that the TNT box is further away from the pig.
Minor bug fixes.
Cleaned up the code.
Merge pull request #194 from nanan9177/maze_skin

PvZ sound effects