Ant extended

Updated build.xml to be version independent... And cleaned up self explanatory comments.
Note the reason i replaced

-    <delete>
-      <fileset dir="${classes}">
-        <include name="**/*.class"/>
-      </fileset>
-    </delete>

with 

+      <delete dir="${classes}"/>
+      <mkdir dir="${classes}"/>

was because ant refused to compile if the classes dir did not exist.