Fix some pokecrystal bug and glitches (#8)

Credits sequence changes move selection menu behavior; Swimming NPCs aren't limited by their movement radius; No bump noise if standing on tile E; The unused phonecall script command may crash; ScriptCall can overflow wScriptStack and crash; LoadSpriteGFX does not limit the capacity of UsedSprites; ReadObjectEvents overflows into wObjectMasks; ClearWRAM only clears WRAM bank 1; BattleAnimCmd_ClearObjs only clears the first 6⅔ objects; Options menu fails to clear joypad state on initialization

home/init.asm

@@ -184,7 +184,6 @@ ClearVRAM::
 ClearWRAM::
 ; Wipe swappable WRAM banks (1-7)
 ; Assumes CGB or AGB
-; BUG: ClearWRAM only clears WRAM bank 1 (see docs/bugs_and_glitches.md)
 
 	ld a, 1
 .bank_loop
@@ -197,7 +196,7 @@ ClearWRAM::
 	pop af
 	inc a
 	cp 8
-	jr nc, .bank_loop
+	jr c, .bank_loop
 	ret
 
 ClearsScratch::

home/map.asm

@@ -573,13 +573,13 @@ ReadObjectEvents::
 	ld a, [wCurMapObjectEventCount]
 	call CopyMapObjectEvents
 
-; get NUM_OBJECTS - [wCurMapObjectEventCount]
-; BUG: ReadObjectEvents overflows into wObjectMasks (see docs/bugs_and_glitches.md)
+; get NUM_OBJECTS - [wCurMapObjectEventCount] - 1
 	ld a, [wCurMapObjectEventCount]
 	ld c, a
-	ld a, NUM_OBJECTS
+	ld a, NUM_OBJECTS - 1
 	sub c
 	jr z, .skip
+	jr c, .skip
 
 	; could have done "inc hl" instead
 	ld bc, 1
@@ -2264,10 +2264,3 @@ LoadMapTileset::
 	pop bc
 	pop hl
 	ret
-
-DummyEndPredef::
-; Unused function at the end of PredefPointers.
-rept 16
-	nop
-endr
-	ret