adds constants, cleans up callstd and msgbox code

* adds some constants for standard script names and messagebox types
* replaces some callstd calls with msgbox calls where equivalent
* replaces msgbox and callstd calls using raw digits with versions that use the constants

data/maps/MauvilleCity_Mart/scripts.inc

@@ -7,7 +7,7 @@ MauvilleCity_Mart_EventScript_2110E6:: @ 82110E6
 	message gUnknown_08272A21
 	waitmessage
 	pokemart MauvilleCity_Mart_Pokemart_211100
-	msgbox gUnknown_08272A3F, 4
+	msgbox gUnknown_08272A3F, MSGBOX_DEFAULT
 	release
 	end
 
@@ -30,11 +30,11 @@ MauvilleCity_Mart_Pokemart_211100: @ 8211100
 	end
 
 MauvilleCity_Mart_EventScript_21111C:: @ 821111C
-	msgbox MauvilleCity_Mart_Text_21112E, 2
+	msgbox MauvilleCity_Mart_Text_21112E, MSGBOX_NPC
 	end
 
 MauvilleCity_Mart_EventScript_211125:: @ 8211125
-	msgbox MauvilleCity_Mart_Text_2111D8, 2
+	msgbox MauvilleCity_Mart_Text_2111D8, MSGBOX_NPC
 	end
 
 MauvilleCity_Mart_Text_21112E: @ 821112E