[SimpleSort] Bring stability improvements to SimpleSort and the classes/methods it relies on

SabreTools.Helper/Objects/SimpleSort.cs

@@ -406,7 +406,6 @@ namespace SabreTools.Helper
 
 			#endregion
 
-			// HERE BE DRAGONS
 			#region Find all files to rebuild and bucket by game
 
 			// Create a dictionary of from/to Rom mappings

SabreTools.Helper/Objects/ZipFIle.cs

@@ -629,7 +629,7 @@ namespace SabreTools.Helper
 			_zipFileInfo = new FileInfo(filename);
 
 			// Now try to open the file
-			_zipstream = File.OpenWrite(filename);
+			_zipstream = File.Open(filename, FileMode.OpenOrCreate, FileAccess.ReadWrite);
 			ZipOpen = ZipOpenType.OpenWrite;
 			return ZipReturn.ZipGood;
 		}