Revamp Pokemon Mansion B2F

This was hell to do. There is still one bug in there, and that's the item pickups don't work for some reason. I don't know how these work honestly so if anyone wants to sort that go ahead.

Anyway, some stuff on the map;
- Currently, a warp from B1F leads there, which is intentionally non-returnable. The player walks through the whole map to get to the warp panel. A walk of humanity's shame, if you will. A warp for where the player is meant to go will be necessary later.
- Lore from Japanese media, particularly the first movie's interpretation of Mewtwo, is included. This is based on context clues on its canonicity from LGPE and other bits.
- A clue on how to get the Old Sea Chart is not-so-subtly included.

The MissingNo. event is unfinished, I intend for Martha to deal with that. The text intentionally lacks a "done" bit to force an unpredictable error; I believe this is inconsequential gameplay-wise and should make for a good opening quote when fighting it.

Oh, and Faraway Island has Mankey, Butterfree, and Primeape as find-able Pokemon now. This should be expanded upon later.

constants/sprite_constants.asm

@@ -51,7 +51,7 @@
 	const SPRITE_FISHER                  ; $2f
 	const SPRITE_KOGA                    ; $30
 	const SPRITE_GUARD                   ; $31
-	const SPRITE_FAKE_TREE               ; $32 - fake tree
+	const SPRITE_FAKE_TREE               ; $32 - fake tree, was guard
 	const SPRITE_MOM                     ; $33
 	const SPRITE_BALDING_GUY             ; $34
 	const SPRITE_LITTLE_BOY              ; $35