Few JavaDoc fixes

Author: christianlacerda

src/main/java/gwt/material/design/client/ui/MaterialSplashScreen.java

@@ -122,6 +122,7 @@ public String getAppDescription() {
 
 	/**
 	 * Optional , you can add your app description on Splash Screen
+	 * @param appDescription Description string
 	 */
 	public void setAppDescription(String appDescription) {
 		this.appDescription = appDescription;

src/main/java/gwt/material/design/client/ui/MaterialTabs.java

@@ -118,6 +118,7 @@ public void addContent(final Widget item) {
 
 	/**
 	 * Initialize the Material Tab
+     * @param ulId Id of the list
 	 */
 	public static native void initTabs(String ulId)/*-{
 		$wnd.jQuery(document).ready(function() {