Organize the engine/ directory, take 3

Renamed `title` to `movies`.
Moved some functions from `engine/routines/` to their fitting
directories, and cleaned up the base `engine/` directory.
Moved `engine/pokemon/tmhm.asm` back to `engine/items/`.

Made a new subdirectory:
* engine/tilesets: Contains all map-related graphics routines.

engine/link/link.asm

@@ -2029,7 +2029,7 @@ Unreferenced_Function28f09: ; 28f09
 	ret
 ; 28f24
 
-INCLUDE "engine/gfx/trade_animation.asm"
+INCLUDE "engine/movie/trade_animation.asm"
 
 CheckTimeCapsuleCompatibility: ; 29bfb
 ; Checks to see if your party is compatible with the Gen 1 games.

engine/link/placewaitingtext.asm

@@ -0,0 +1,24 @@
+PlaceWaitingText:: ; 4000
+	hlcoord 3, 10
+	ld b, 1
+	ld c, 11
+
+	ld a, [wBattleMode]
+	and a
+	jr z, .notinbattle
+
+	call TextBox
+	jr .proceed
+
+.notinbattle
+	predef LinkTextboxAtHL
+
+.proceed
+	hlcoord 4, 11
+	ld de, .Waiting
+	call PlaceString
+	ld c, 50
+	jp DelayFrames
+
+.Waiting: ; 4025
+	db "Waiting...!@"