Organize the engine/ directory

This is an informed attempt at reorganizing the engine/ directory by
creating categorized subdirectories, in order to make it easier to
navigate and find things.

The directories created are as follows:
* engine/game: Contains all "minigames", things like the unown puzzle
and slot machine.
* engine/gfx: Contains all handling of graphics. From loading palettes
to playing animations.
* engine/link: Contains all multiplayer functionality.
* engine/menu: Contains all generic/misc. menus and menu code.
Other, more specialized menus are in their own subdirectories (pokedex,
pokegear, party menu, etc).
* engine/overworld: Contains all handling of the overworld. From loading
and connecting maps to wild encounters and the scripting engine.
* engine/pokegear: In the same vein as engine/pokedex, except it could
use some more splitting up.
* engine/pokemon: Contains everything related to manipulating pokemon
data. From the pokemon storage system to evolution and mail.
* engine/printer: Contains everything related to printing things as well
as the printer communication.
* engine/title: Contains intro sequences, title screens and credits.

engine/overworld/spawn_points.asm

@@ -0,0 +1,62 @@
+INCLUDE "data/maps/spawn_points.asm"
+
+
+LoadSpawnPoint: ; 1531f
+	; loads the spawn point in wDefaultSpawnpoint
+	push hl
+	push de
+	ld a, [wDefaultSpawnpoint]
+	cp SPAWN_N_A
+	jr z, .spawn_n_a
+	ld l, a
+	ld h, 0
+	add hl, hl
+	add hl, hl
+	ld de, SpawnPoints
+	add hl, de
+	ld a, [hli]
+	ld [wMapGroup], a
+	ld a, [hli]
+	ld [wMapNumber], a
+	ld a, [hli]
+	ld [wXCoord], a
+	ld a, [hli]
+	ld [wYCoord], a
+.spawn_n_a
+	pop de
+	pop hl
+	ret
+; 15344
+
+
+IsSpawnPoint: ; 15344
+; Checks if the map loaded in de is a spawn point.  Returns carry if it's a spawn point.
+	ld hl, SpawnPoints
+	ld c, 0
+.loop
+	ld a, [hl]
+	cp SPAWN_N_A
+	jr z, .nope
+	cp d
+	jr nz, .next
+	inc hl
+	ld a, [hld]
+	cp e
+	jr z, .yes
+
+.next
+	push bc
+	ld bc, 4 ; length of a spawn table entry
+	add hl, bc
+	pop bc
+	inc c
+	jr .loop
+
+.nope
+	and a
+	ret
+
+.yes
+	scf
+	ret
+; 15363