New Flutter Animation

This app contains these demos.
1. Birds
2. Fireworks
3. Sphere
4. Cards
5. Ambient background
6. Wind
7. Ripple
8. Rays
9. Sun
10. Calendar animation
11. Particles on path
12. Shimmering
13. Confetti
14. Comet trail
15. Cloud Sim
16. Snow Sim
17. Fireball
18. Helicity
19. Troika