Split items/ and trainers/ into their data/ and engine/ components

Move some data into a pokemon/ subdirectory

data/pokemon/base_stats/shellder.asm

@@ -0,0 +1,22 @@
+	db SHELLDER ; 090
+
+	db  30,  65, 100,  40,  45,  25
+	;   hp  atk  def  spd  sat  sdf
+
+	db WATER, WATER
+	db 190 ; catch rate
+	db 97 ; base exp
+	db PEARL ; item 1
+	db BIG_PEARL ; item 2
+	db GENDER_F50 ; gender
+	db 100 ; unknown
+	db 20 ; step cycles to hatch
+	db 5 ; unknown
+	INCBIN "gfx/pics/shellder/front.dimensions"
+	db 0, 0, 0, 0 ; padding
+	db SLOW ; growth rate
+	dn INVERTEBRATE, INVERTEBRATE ; egg groups
+
+	; tmhm
+	tmhm CURSE, TOXIC, HIDDEN_POWER, SNORE, BLIZZARD, ICY_WIND, PROTECT, RAIN_DANCE, ENDURE, FRUSTRATION, RETURN, DOUBLE_TEAM, SWAGGER, SLEEP_TALK, SWIFT, REST, ATTRACT, SURF, WHIRLPOOL, ICE_BEAM
+	; end