magic's build.xml has bad install target

The /tools/magic/build.xml file contains a bad 'install' target defintion - the current "install@ task needs to replaced by the following:

<target name="update" depends="install">
<mkdir dir="${user.home}/.ant/lib"/>
<copy toDir="${user.home}/.ant/lib"
file="${basedir}/target/deliverables/jars/${project.filename}"/>
</target>

This effectly makes updating of ${user.home}/.ant/lib an explict action instead of a default action. The change is needed as a virgin build will fail due to the jvm getting itself confused when magic is in the classloader and magic is being updated.