Add trainers to Celadon University, add two new salesmen, etc

Overall completes Celadon University sans a problem with sprites being a bit corrupted until you leave. New Magikarp Salesman-esque events in other pokecenters which is kinda neat

scripts/RockTunnelPokecenter.asm

@@ -7,6 +7,7 @@ RockTunnelPokecenter_TextPointers:
 	dw RockTunnelPokecenterText2
 	dw RockTunnelPokecenterText3
 	dw RockTunnelTradeNurseText
+	dw DittoSalesmanText
 
 RockTunnelHealNurseText:
 	script_pokecenter_nurse
@@ -21,3 +22,68 @@ RockTunnelPokecenterText3:
 
 RockTunnelTradeNurseText:
 	script_cable_club_receptionist
+
+DittoSalesmanText:
+	text_asm
+	CheckEvent EVENT_BOUGHT_DITTO, 1
+	jp c, .alreadyBoughtDitto
+	ld hl, .Text1
+	call PrintText
+	ld a, MONEY_BOX
+	ld [wTextBoxID], a
+	call DisplayTextBoxID
+	call YesNoChoice
+	ld a, [wCurrentMenuItem]
+	and a
+	jp nz, .choseNo
+	ldh [hMoney], a
+	ldh [hMoney + 2], a
+	ld a, $5
+	ldh [hMoney + 1], a
+	call HasEnoughMoney
+	jr nc, .enoughMoney
+	ld hl, .NoMoneyText
+	jr .printText
+.enoughMoney
+	lb bc, DITTO, 23
+	call GivePokemon
+	jr nc, .done
+	xor a
+	ld [wPriceTemp], a
+	ld [wPriceTemp + 2], a
+	ld a, $5
+	ld [wPriceTemp + 1], a
+	ld hl, wPriceTemp + 2
+	ld de, wPlayerMoney + 2
+	ld c, $3
+	predef SubBCDPredef
+	ld a, MONEY_BOX
+	ld [wTextBoxID], a
+	call DisplayTextBoxID
+	SetEvent EVENT_BOUGHT_DITTO
+	jr .done
+.choseNo
+	ld hl, .RefuseText
+	jr .printText
+.alreadyBoughtDitto
+	ld hl, .Text2
+.printText
+	call PrintText
+.done
+	jp TextScriptEnd
+
+.Text1
+	text_far _DittoSalesmanText1
+	text_end
+
+.RefuseText
+	text_far _DittoSalesmanNoText
+	text_end
+
+.NoMoneyText
+	text_far _DittoSalesmanNoMoneyText
+	text_end
+
+.Text2
+	text_far _DittoSalesmanText2
+	text_end