Progress on New Save Format

Integrated the base code for our new save format. It still needs more
work but at least some substance is there. Ignore the file not found
messages that come up when trying to save the world's data - since we're
not actually writing files, an exception occurs when we some later code
tries to move non-existent save files.

Also moved the FileFilter functionality out of DungeonHelper and into
its own class, FileFilters, since it's finally needed more broadly.

StevenDimDoors/mod_pocketDim/util/FileFilters.java

@@ -0,0 +1,51 @@
+package StevenDimDoors.mod_pocketDim.util;
+
+import java.io.File;
+import java.io.FileFilter;
+import java.util.regex.Pattern;
+
+public class FileFilters
+{
+	private FileFilters() { }
+	
+	public static class DirectoryFilter implements FileFilter
+	{
+		@Override
+		public boolean accept(File file)
+		{
+			return file.isDirectory();
+		}
+	}
+	
+	public static class FileExtensionFilter implements FileFilter
+	{
+		private final String extension;
+		
+		public FileExtensionFilter(String extension)
+		{
+			this.extension = extension;
+		}
+		
+		@Override
+		public boolean accept(File file)
+		{
+			return file.isFile() && file.getName().endsWith(extension);
+		}
+	}
+	
+	public static class RegexFileFilter implements FileFilter
+	{
+		private final Pattern pattern;
+		
+		public RegexFileFilter(String expression)
+		{
+			this.pattern = Pattern.compile(expression);
+		}
+		
+		@Override
+		public boolean accept(File file)
+		{
+			return file.isFile() && pattern.matcher(file.getName()).matches();
+		}
+	}
+}