Citrine geography rework, Metal Coat

Lots of things here. Citrine now has its own tileset featuring content from the prototype asset leak. This includes new grass, signs, and so on. Lots of tinkering had to be done to make it look good, but it does! Collision and everything is done, but grass needs to animate properly. I'm committing as-is because making the grass animate is actually very difficult.

Also added the Metal Coat and fixed the issues with prior evolution methods - evo items first, level-up second. It is currently unobtainable.

constants/item_constants.asm

@@ -100,6 +100,7 @@ DEF SAFARI_ROCK EQU $16 ; overload
 	const CITRINE_PASS  ; $59
 	const OLD_SEA_MAP	; $5A
 	const UP_GRADE		; $5B
+	const METAL_COAT	; $5C
 DEF NUM_ITEMS EQU const_value - 1
 
 ; elevator floors use item IDs

constants/pokemon_constants.asm

@@ -98,7 +98,7 @@
 	const DRAGONAIR          ; $59
 	const KABUTO             ; $5A
 	const KABUTOPS           ; $5B - Up-Grade (Evo Stone Glitch)
-	const HORSEA             ; $5C
+	const HORSEA             ; $5C - Metal Coat (Evo Stone Glitch)
 	const SEADRA             ; $5D
 	const BAWLIGUA           ; $5E	(new)
 	const CRYITHAN           ; $5F	(new)

constants/tileset_constants.asm

@@ -26,4 +26,5 @@
 	const FACILITY     ; 22
 	const PLATEAU      ; 23
 	const PREGYM	   ; 24
+	const CITRINE	   ; 25
 DEF NUM_TILESETS EQU const_value