Only build plugins that don't exist or have been modified

Fixes issue 2125

createPluginJar.sh

 	exit;
 fi
 
+srcdir=${PWD}
 pluginname=${1}
 foldername=${pluginname//.//}
 
+newer=`find src/${foldername} -type f -newer ${srcdir}/plugins/${2}.jar 2>&1 | wc -l`
+
+if [ $newer -eq 0 ]; then
+	echo "${2}.jar appears to be up-to-date";
+	exit 0;
+fi
+
 echo "Creating ${2}.jar for ${pluginname} (${foldername})"
 
 if [ ! -e src/${foldername}/plugin.info -a ! -e src/${foldername}/plugin.config ]; then
 fi
 
 #echo "looking for classes"
-srcdir=${PWD}
 TMPDIR=`mktemp -d`
 #echo "Using temp dir: ${TMPDIR}"
 cd $TMPDIR