Add Bellignan, fix evo stones

My first foray into adding Pokemon, here's Bellignan! Imported the sprite animation from Pokemon October. Works like a charm!

I also fixed the new evo stones, which didn't have their effects assigned yet.

constants/pokemon_constants.asm

@@ -90,6 +90,7 @@
 	const BELLSPROUT ; 45
 	const WEEPINBELL ; 46
 	const VICTREEBEL ; 47
+	const BELLIGNAN
 	const TENTACOOL  ; 48
 	const TENTACRUEL ; 49
 	const GEODUDE    ; 4a