MNG-628: No more clover.html + no more site resources generated. Done this time by extending AbstractMavenReport and overriding it's main methods (generate() and execute()). AbstractMavenReport would need to add native support for external reports to have something clean (see MNG-645)
maven/components/trunk/maven-plugins/maven-clover-plugin/src/main/java/org/apache/maven/plugin/clover/CloverReportMojo.java