Removed an unused timer on Projectiles

TODO.txt

@@ -9,7 +9,8 @@ o Make things less difficult and more interesting
 
 o Creat some nice room modifiers
 	x Windy room
-	- Liquid in rooms
+	x Liquid in rooms
+	- Falling floor tiles
 
 - Credit screen showing music and graphics guys:
 	- Music: http://soundimage.org/ (Eric Matyas)

src/projectile.h

@@ -37,7 +37,6 @@ typedef struct Projectile_t {
 	Vector2d velocity;
 	Timer *lifetime;
 	bool alive;
-	Timer *animation_timer;
 	void (*onRender)(struct Projectile_t*);
 } Projectile;