Remove our naive Maven Log implementation

Maven is now using SLF4J, so might as well use it too!

Author: jeffgbutler

core/mybatis-generator-maven-plugin/src/main/java/org/mybatis/generator/maven/MavenLogFactory.java

@@ -42,9 +42,6 @@
 import org.mybatis.generator.internal.util.ClassloaderUtility;
 import org.mybatis.generator.internal.util.StringUtility;
 import org.mybatis.generator.internal.util.messages.Messages;
-import org.mybatis.generator.logging.LogFactory;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 /**
  * Goal which generates MyBatis artifacts.
@@ -165,8 +162,6 @@ public void execute() throws MojoExecutionException {
 
         saveClassLoader();
 
-        LogFactory.setLogFactory(new MavenLogFactory(this));
-
         calculateClassPath();
 
         // add resource directories to the classpath.  This is required to support