add NullInputStream

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

@@ -0,0 +1,13 @@
+package org.cobbzilla.util.io;
+
+import java.io.InputStream;
+
+public class NullInputStream extends InputStream {
+
+    public static final NullInputStream instance = new NullInputStream();
+
+    @Override public int read() { return -1; }
+    @Override public int read(byte[] b) { return -1; }
+    @Override public int read(byte[] b, int off, int len) { return -1; }
+
+}