Physac redesign (3/3)

Finally, physics update is handled in main thread using steps to get
accuracy in collisions detection instead of moving it to a new thread.

Examples are finished as simple and clear as I could. Finally, physac
module is MORE simpler than in the first version, calculation everything
by the same way for both types of physic objects.

I tryed to add rotated physics a couple of times but I didn't get
anything good to get a base to improve it. Maybe for the next version...

No bugs or strange behaviours found during testing.

src/raylib.h

@@ -498,8 +498,8 @@ typedef enum { COLLIDER_CIRCLE, COLLIDER_RECTANGLE } ColliderType;
 
 typedef struct Transform {
     Vector2 position;
-    float rotation;
-    Vector2 scale;
+    float rotation;         // Radians (not used)
+    Vector2 scale;          // Just for rectangle physic objects, for circle physic objects use collider radius and keep scale as { 0, 0 }
 } Transform;
 
 typedef struct Rigidbody {