add NullOutputStream

src/main/java/org/cobbzilla/util/io/NullOutputStream.java

@@ -0,0 +1,15 @@
+package org.cobbzilla.util.io;
+
+import java.io.OutputStream;
+
+public class NullOutputStream extends OutputStream {
+
+    public static final NullOutputStream NULL_OUTPUT_STREAM = new NullOutputStream();
+
+    @Override public void write(int b) {}
+    @Override public void write(byte[] b) {}
+    @Override public void write(byte[] b, int off, int len) {}
+    @Override public void flush() {}
+    @Override public void close() {}
+
+}