Add constants and table macros for the map sprite sets (#392)

Fixes #391

constants/sprite_set_constants.asm

@@ -0,0 +1,38 @@
+; sprite set ids
+; indexes for SpriteSets (see data/maps/sprite_sets.asm)
+; values for MapSpriteSets and SplitMapSpriteSets (see data/maps/sprite_sets.asm)
+	const_def 1
+	const SPRITESET_PALLET_VIRIDIAN ; 01
+	const SPRITESET_PEWTER_CERULEAN ; 02
+	const SPRITESET_LAVENDER        ; 03
+	const SPRITESET_VERMILION       ; 04
+	const SPRITESET_CELADON         ; 05
+	const SPRITESET_INDIGO          ; 06
+	const SPRITESET_SAFFRON         ; 07
+	const SPRITESET_SILENCE_BRIDGE  ; 08
+	const SPRITESET_CYCLING_ROAD    ; 09
+	const SPRITESET_FUCHSIA         ; 0a
+DEF NUM_SPRITE_SETS EQU const_value - 1
+
+; split sprite set ids
+; indexes for SplitMapSpriteSets (see data/maps/sprite_sets.asm)
+; values for MapSpriteSets (see data/maps/sprite_sets.asm)
+	const_next $f1
+DEF FIRST_SPLIT_SET EQU const_value
+	const SPLITSET_ROUTE_2  ; f1
+	const SPLITSET_ROUTE_10 ; f2
+	const SPLITSET_ROUTE_11 ; f3
+	const SPLITSET_ROUTE_12 ; f4
+	const SPLITSET_ROUTE_15 ; f5
+	const SPLITSET_ROUTE_16 ; f6
+	const SPLITSET_ROUTE_18 ; f7
+	const SPLITSET_ROUTE_20 ; f8
+	const SPLITSET_ROUTE_5  ; f9
+	const SPLITSET_ROUTE_6  ; fa
+	const SPLITSET_ROUTE_7  ; fb
+	const SPLITSET_ROUTE_8  ; fc
+DEF NUM_SPLIT_SETS EQU const_value - FIRST_SPLIT_SET
+
+; split directions
+DEF EAST_WEST   EQU 1
+DEF NORTH_SOUTH EQU 2