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/init_map.asm

@@ -0,0 +1,103 @@
+ReanchorBGMap_NoOAMUpdate:: ; 6454
+	call DelayFrame
+	ld a, [hOAMUpdate]
+	push af
+
+	ld a, $1
+	ld [hOAMUpdate], a
+	ld a, [hBGMapMode]
+	push af
+	xor a
+	ld [hBGMapMode], a
+
+	call .ReanchorBGMap
+
+	pop af
+	ld [hBGMapMode], a
+	pop af
+	ld [hOAMUpdate], a
+	ld hl, wVramState
+	set 6, [hl]
+	ret
+
+.ReanchorBGMap:
+	xor a
+	ld [hLCDCPointer], a
+	ld [hBGMapMode], a
+	ld a, $90
+	ld [hWY], a
+	call OverworldTextModeSwitch
+	ld a, HIGH(vBGMap1)
+	call .LoadBGMapAddrIntoHRAM
+	call _OpenAndCloseMenu_HDMATransferTileMapAndAttrMap
+	farcall LoadOW_BGPal7
+	farcall ApplyPals
+	ld a, $1
+	ld [hCGBPalUpdate], a
+	xor a
+	ld [hBGMapMode], a
+	ld [hWY], a
+	farcall HDMATransfer_FillBGMap0WithBlack ; no need to farcall
+	ld a, HIGH(vBGMap0)
+	call .LoadBGMapAddrIntoHRAM
+	xor a ; LOW(vBGMap0)
+	ld [wBGMapAnchor], a
+	ld a, HIGH(vBGMap0)
+	ld [wBGMapAnchor + 1], a
+	xor a
+	ld [hSCX], a
+	ld [hSCY], a
+	call ApplyBGMapAnchorToObjects
+	ret
+
+.LoadBGMapAddrIntoHRAM: ; 64b9
+	ld [hBGMapAddress + 1], a
+	xor a
+	ld [hBGMapAddress], a
+	ret
+
+LoadFonts_NoOAMUpdate:: ; 64bf
+	ld a, [hOAMUpdate]
+	push af
+	ld a, $1
+	ld [hOAMUpdate], a
+
+	call .LoadGFX
+
+	pop af
+	ld [hOAMUpdate], a
+	ret
+
+.LoadGFX:
+	call LoadFontsExtra
+	ld a, $90
+	ld [hWY], a
+	call SafeUpdateSprites
+	call LoadStandardFont
+	ret
+
+HDMATransfer_FillBGMap0WithBlack: ; 64db
+	ld a, [rSVBK]
+	push af
+	ld a, BANK(wDecompressScratch)
+	ld [rSVBK], a
+
+	ld a, "■"
+	ld hl, wDecompressScratch
+	ld bc, wScratchAttrMap - wDecompressScratch
+	call ByteFill
+	ld a, HIGH(wDecompressScratch)
+	ld [rHDMA1], a
+	ld a, LOW(wDecompressScratch)
+	ld [rHDMA2], a
+	ld a, HIGH(vBGMap0 % $8000)
+	ld [rHDMA3], a
+	ld a, LOW(vBGMap0 % $8000)
+	ld [rHDMA4], a
+	ld a, $3f
+	ld [hDMATransfer], a
+	call DelayFrame
+
+	pop af
+	ld [rSVBK], a
+	ret