Adding programmatic configuration for Hazelcast in embedded vert.x

For programatically configuring the hazelcast cluster before starting vert (embedded).  Useful if you want cluster configuration to be determined at startup time.

Usage:

    Config cfg = new Config();
    ProgrammableClusterManagerFactory.setConfig(cfg);
    System.setProperty("vertx.clusterManagerFactory", ProgrammableClusterManagerFactory.class.getName());

    NetworkConfig network = cfg.getNetworkConfig();
    network.setPort(5900);
    network.setPortAutoIncrement(false);
    Join join = network.getJoin();
    join.getMulticastConfig().setEnabled(false);
    join.getTcpIpConfig().addMember("10.45.67.32").addMember("10.45.67.100").setEnabled(true);

    PlatformManager pm = PlatformLocator.factory.createPlatformManager(1234,"127.0.0.1");

Signed-off-by: Dean Pehrsson-Chapman <dean@p14n.com>