Utils: Add main classes to i2p.jar and router.jar

for simple command line access to utilities

core/java/build.xml

@@ -58,6 +58,7 @@
                 <attribute name="Built-By" value="${build.built-by}" />
                 <attribute name="Build-Date" value="${build.timestamp}" />
                 <attribute name="Base-Revision" value="${workspace.version}" />
+                <attribute name="Main-Class" value="net.i2p.util.CommandLine" />
                 <attribute name="Workspace-Changes" value="${workspace.changes.tr}" />
             </manifest>
         </jar>