remove sourceforge link in javadoc footer

javadoc.gradle

@@ -15,7 +15,7 @@ def javadocOptions = {
 	options.addStringOption("-source ${version}")
 }
 def footerMessage = '<p class="legalCopy"><small>Copyright &copy; 2005-' + "${currentYear}" + ' Potix Corporation. All Rights Reserved.\n' +
-		'<a href="https://sourceforge.net"><img src="https://sourceforge.net/sflogo.php?group_id=152762&amp;type=1" width="88" height="31" border="0" alt="SourceForge.net Logo" /></a><script type="text/javascript">if (location.href.indexOf(\'zkoss.org\') >= 0) {var gaJsHost = (("https:" == document.location.protocol) ? "https://ssl." : "http://www.");document.write(unescape("%3Cscript src=\'" + gaJsHost + "google-analytics.com/ga.js\' type=\'text/javascript\'%3E%3C/script%3E"));}</script><script type="text/javascript">if (location.href.indexOf(\'zkoss.org\') >= 0) {var pageTracker = _gat._getTracker("UA-121377-3");pageTracker._setDomainName("zkoss.org");pageTracker._initData();pageTracker._trackPageview();}</script>\n' +
+		'<script type="text/javascript">if (location.href.indexOf(\'zkoss.org\') >= 0) {var gaJsHost = (("https:" == document.location.protocol) ? "https://ssl." : "http://www.");document.write(unescape("%3Cscript src=\'" + gaJsHost + "google-analytics.com/ga.js\' type=\'text/javascript\'%3E%3C/script%3E"));}</script><script type="text/javascript">if (location.href.indexOf(\'zkoss.org\') >= 0) {var pageTracker = _gat._getTracker("UA-121377-3");pageTracker._setDomainName("zkoss.org");pageTracker._initData();pageTracker._trackPageview();}</script>\n' +
 		'\t </small></p>\n'
 
 def addJavadocFooter(dir, footerMessage) {