Organize the engine/ directory, take 2

Renamed `game` to `games` and `menu` to `menus`.
Moved some functions from `engine/routines/` to their fitting subdirectories.

Made two new subdirectories:
* engine/rtc: Contains all RTC-related things. Menus, hardware, misc
functions.
* engine/items: Contains all item-related things. Pack, item effects,
other item handlers.

engine/items/tmhm.asm

@@ -0,0 +1,49 @@
+CanLearnTMHMMove: ; 11639
+	ld a, [wCurPartySpecies]
+	ld [wCurSpecies], a
+	call GetBaseData
+	ld hl, wBaseTMHM
+	push hl
+
+	ld a, [wPutativeTMHMMove]
+	ld b, a
+	ld c, 0
+	ld hl, TMHMMoves
+.loop
+	ld a, [hli]
+	and a
+	jr z, .end
+	cp b
+	jr z, .asm_11659
+	inc c
+	jr .loop
+
+.asm_11659
+	pop hl
+	ld b, CHECK_FLAG
+	push de
+	ld d, 0
+	predef SmallFarFlagAction
+	pop de
+	ret
+
+.end
+	pop hl
+	ld c, 0
+	ret
+; 1166a
+
+GetTMHMMove: ; 1166a
+	ld a, [wd265]
+	dec a
+	ld hl, TMHMMoves
+	ld b, 0
+	ld c, a
+	add hl, bc
+	ld a, [hl]
+	ld [wd265], a
+	ret
+; 1167a
+
+
+INCLUDE "data/moves/tmhm_moves.asm"