Effects Update

Hello, 

I've experimented with new effects in SSmini a while ago, and since I was done with them, I might as well update it as whole.

New effects added:
- ship and rocket Explosions
- growing ring by hitting or getting items
- muzzle from shooting
- new fire particles for the fire ship
- animated explosion from the purple ship

Also, you can now change ships on the fly by holding Z and then pressing left or right. So all ships have now a combined effort!
(The ship's level is retained during a ship change)

And that's about it, have fun :)