Usage:

<taskdef name="fileprefixer" classname="org.bellard.fileprefixer.FilePrefixerTask" classpath="dist/file-prefixer-0.0.1.jar"/>
<fileprefixer toprefix="build/eqemu-licence.txt" todir="dist" verbose="true">
   fileset dir="dist">
      <include name="**/*.java"/>
   </fileset>
</fileprefixer>