fix SLF4J-514

Author: ceki

log4j-over-slf4j/src/main/java/org/apache/log4j/ConsoleAppender.java

@@ -15,6 +15,18 @@
  */
 package org.apache.log4j;
 
+/**
+ * Skeleton implementation of ConsoleAppender
+ */
 public class ConsoleAppender extends WriterAppender {
 
+    public ConsoleAppender() {
+    }
+
+    public ConsoleAppender(Layout layout) {
+    }
+
+    public ConsoleAppender(Layout layout, String target) {
+    }
+
 }