nes-clarify relationship between mapper 115 and mapper 248 (and support 248)

BizHawk.Emulation/Consoles/Nintendo/Docs/compatibility.txt

@@ -125,3 +125,4 @@ Open bus and bus conflict emulation is not considered complete or thorough in an
 243	Misc		Nothing
 245	Pirate		Junk
 246	Misc (CN)	Nothing
+248 Misc (CN)	{{See 115}} 

BizHawk.Emulation/Consoles/Nintendo/NES/Boards/MMC3_family/Mapper115.cs

@@ -4,6 +4,9 @@ using System.Diagnostics;
 
 namespace BizHawk.Emulation.Consoles.Nintendo
 {
+	//this class also handles mapper 248
+	//FCEUX uses 115 to implement 248 as well (as of 09-apr-2012 it does it buggily in the case of Bao Qing Tian (As))
+	//VirtuaNES has its own class that implements 248. I think it's wrong (MAME and/or MESS may have switched to using 115 at some point)
 	public class Mapper115 : MMC3Board_Base
 	{
 		public override bool Configure(NES.EDetectionOrigin origin)
@@ -12,6 +15,7 @@ namespace BizHawk.Emulation.Consoles.Nintendo
 			switch (Cart.board_type)
 			{
 				case "MAPPER115":
+				case "MAPPER248":
 					break;
 				default:
 					return false;

BizHawk.Emulation/Consoles/Nintendo/NES/iNES.cs

@@ -118,6 +118,7 @@ static string ClassifyTable = @"
 232	-1	-1	-1	-1	MAPPER232
 240	-1	-1	-1	-1	MAPPER240
 242	-1	-1	-1	-1	MAPPER242
+248	-1	-1	-1	-1	MAPPER248
 ";
 }