Sevii Region groundwork

This adds the baseline infrastructure to account for the Sevii Islands, while also fixing a couple of bugs. Zeta, please read the commit carefully!

Only real issue I noticed was that scrolling on the town map is infinite in all three new regions, implying there's something in `pokegear.asm` I haven't accounted for.

I've also ret'd the ezchat order and gen1 orders out of existence to reduce the sheer amount of 8-bit warnings. This abolishes gen1 compatibility (though this was already a bit fucked) in exchange for actually being able to debug things in a reasonable timeframe.

constants/engine_flags.asm

@@ -98,6 +98,13 @@
 	const ENGINE_FLYPOINT_LAKE_OF_RAGE
 	const ENGINE_FLYPOINT_BLACKTHORN
 	const ENGINE_FLYPOINT_SILVER_CAVE
+	const ENGINE_FLYPOINT_ONE_ISLAND
+	const ENGINE_FLYPOINT_TWO_ISLAND
+	const ENGINE_FLYPOINT_THREE_ISLAND
+	const ENGINE_FLYPOINT_FOUR_ISLAND
+	const ENGINE_FLYPOINT_FIVE_ISLAND
+	const ENGINE_FLYPOINT_SIX_ISLAND
+	const ENGINE_FLYPOINT_SEVEN_ISLAND
 	const ENGINE_FLYPOINT_SILENT_HILLS
 	const ENGINE_FLYPOINT_OLD
 	const ENGINE_FLYPOINT_UNUSED

constants/landmark_constants.asm

@@ -118,11 +118,13 @@ DEF KANTO_LANDMARK EQU const_value
 	const LANDMARK_TOHJO_FALLS       ; 5d
 	const LANDMARK_ROUTE_28          ; 5e
 	const LANDMARK_FAST_SHIP         ; 5f
-    const LANDMARK_ONE_ISLAND
+DEF SEVII_LANDMARK_1 EQU const_value
+	const LANDMARK_ONE_ISLAND
 	const LANDMARK_TWO_ISLAND
 	const LANDMARK_THREE_ISLAND
 	const LANDMARK_FOUR_ISLAND
 	const LANDMARK_FIVE_ISLAND
+DEF SEVII_LANDMARK_2 EQU const_value
 	const LANDMARK_SIX_ISLAND
 	const LANDMARK_SEVEN_ISLAND
 DEF NIHON_LANDMARK EQU const_value
@@ -148,5 +150,7 @@ DEF NUM_LANDMARKS EQU const_value
 	const_def
 	const JOHTO_REGION ; 0
 	const KANTO_REGION ; 1
-	const NIHON_REGION ; 2
+	const SEVII_REGION_1 ; 2
+	const SEVII_REGION_2 ; 3
+	const NIHON_REGION ; 4
 DEF NUM_REGIONS EQU const_value

constants/map_data_constants.asm

@@ -102,6 +102,15 @@ DEF NUM_FISHGROUPS EQU const_value - 1
 	const SPAWN_BLACKTHORN
 	const SPAWN_MT_SILVER
 	const SPAWN_FAST_SHIP
+; sevii 1
+	const SPAWN_ONE_ISLAND
+	const SPAWN_TWO_ISLAND
+	const SPAWN_THREE_ISLAND
+	const SPAWN_FOUR_ISLAND
+	const SPAWN_FIVE_ISLAND
+; sevii 2
+	const SPAWN_SIX_ISLAND
+	const SPAWN_SEVEN_ISLAND
 ; nihon
 	const SPAWN_SILENT_HILLS
 	const SPAWN_OLD_CITY
@@ -139,6 +148,15 @@ DEF KANTO_FLYPOINT EQU const_value
 	const FLY_FUCHSIA
 	const FLY_CINNABAR
 	const FLY_INDIGO
+DEF SEVII_FLYPOINT_1 EQU const_value ; 1-5
+	const FLY_ONE_ISLAND
+	const FLY_TWO_ISLAND
+	const FLY_THREE_ISLAND
+	const FLY_FOUR_ISLAND
+	const FLY_FIVE_ISLAND
+DEF SEVII_FLYPOINT_2 EQU const_value ; 6-7
+	const FLY_SIX_ISLAND
+	const FLY_SEVEN_ISLAND
 DEF NIHON_FLYPOINT EQU const_value
 	const FLY_SILENT_HILLS
 	const FLY_OLD_CITY