private static File getExtensionPath() {
        return new File(System.getProperty("user.dir"), "ext");
    }
Command line installer for plugins to Gremlin Server.

@author Stephen Mallette (http://stephen.genoprime.com)
gremlin-server/src/main/java/org/apache/tinkerpop/gremlin/server/util/GremlinServerInstall.java