Use Serializable representation of system supplied motors in jar file.

this greatly improves startup performance.

core/build.xml

@@ -68,7 +68,7 @@
 	</target>
 	
 	<!-- Executible Eclipse-Jar-In-Jar style JAR -->
-	<target name="jar" depends="core-jar,serialize-presets" description="Create the OpenRocket jar-in-jar Executable">
+	<target name="jar" depends="core-jar,serialize-presets,serialize-motors" description="Create the OpenRocket jar-in-jar Executable">
 		<mkdir dir="${jar.dir}" />
 		<jar destfile="${jar.file}">
 			<manifest>
@@ -110,6 +110,13 @@
 			  classpathref="run-classpath"
 			  failonerror="true">
 	    </java>
+	</target>
+	<target name="serialize-motors" depends="core-jar" description="Preprocess the motor files into serialized form">
+	    <java classname="net.sf.openrocket.startup.SerializeMotors"
+	          fork="true"
+			  classpathref="run-classpath"
+			  failonerror="true">
+	    </java>
 	</target>
 		<!-- Core OpenRocket JAR -->
 	<target name="core-jar" depends="build" description="Create the OpenRocket code-only jar file">