Changes to javadoc generation

Change "Google Web Toolkit" to "GWT", use "-source ${javac.source}"
instead of "-source 1.5" and add "-noindex -notree" to avoid generating
big files that nobody uses and wouldn't fit gwtproject.org constraints.

Change-Id: I85170407b11e27e8c8ff5fb2db77c46936205db5
diff --git a/doc/build.xml b/doc/build.xml
index f0319ff..53fcbc7 100644
--- a/doc/build.xml
+++ b/doc/build.xml
@@ -82,15 +82,17 @@
     <property file="${gwt.root}/build/out/packages.properties" />
     <java classpathref="DOC_PATH" classname="com.google.doctool.custom.GWTJavaDoclet" fork="yes" failonerror="true">
       <jvmarg value="-Xmx1024m" />
+      <arg value="-noindex" />
+      <arg value="-notree" />
       <arg value="-quiet" />
       <arg value="-notimestamp" />
       <arg value="-use" />
       <arg value="-source" />
-      <arg value="1.5" />
+      <arg value="${javac.source}" />
       <arg value="-windowtitle" />
-      <arg value="Google Web Toolkit Javadoc" />
+      <arg value="GWT Javadoc" />
       <arg value="-doctitle" />
-      <arg value="Google Web Toolkit API Reference" />
+      <arg value="GWT API Reference" />
       <arg value="-header" />
       <arg value="GWT ${gwt.version}" />
       <arg value="-package" />