The current ConsoleAppender implementation is empty, without any constructors or methods. This results in an incompatibility for one of our projects dependency:

java.lang.NoSuchMethodError: org.apache.log4j.ConsoleAppender.<init>(Lorg/apache/log4j/Layout;)V
	at logging.xxxFactory.getLogger(xxxFactory.java:26)

The `FileAppender` provides the needed constructors. The mocking implementation should provide all constructors and (optionally) methods exposed by the original class.
PR available at https://github.com/qos-ch/slf4j/pull/259/