Extract DevNull OutputStream to its own class

Extract DevNull to its own class, so that it can be used by other
classes.

src/main/java/ctbrec/DevNull.java

@@ -0,0 +1,18 @@
+package ctbrec;
+
+import java.io.IOException;
+import java.io.OutputStream;
+
+public class DevNull extends OutputStream {
+    @Override
+    public void write(int b) throws IOException {
+    }
+
+    @Override
+    public void write(byte[] b) throws IOException {
+    }
+
+    @Override
+    public void write(byte[] b, int off, int len) throws IOException {
+    }
+}

src/main/java/ctbrec/ui/Player.java

@@ -1,13 +1,12 @@
 package ctbrec.ui;
 
 import java.io.File;
-import java.io.IOException;
-import java.io.OutputStream;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import ctbrec.Config;
+import ctbrec.DevNull;
 import ctbrec.Recording;
 import ctbrec.recorder.OS;
 import ctbrec.recorder.StreamRedirectThread;
@@ -48,6 +47,7 @@ public class Player {
         }
     }
 
+
     private static class PlayerThread extends Thread {
         private boolean running = false;
         private Process playerProcess;
@@ -113,18 +113,4 @@ public class Player {
             }
         }
     }
-
-    private static class DevNull extends OutputStream {
-        @Override
-        public void write(int b) throws IOException {
-        }
-
-        @Override
-        public void write(byte[] b) throws IOException {
-        }
-
-        @Override
-        public void write(byte[] b, int off, int len) throws IOException {
-        }
-    }
-}
+}