message: separate http-serving part of service to own start function
diff: -use std::sync::Arc;
  -use iron::Iron;
  +use config::{Config, Networks};
  use handlers;
  +use iron::Iron;
  use router::Router;
  -use config::Config;
  +use std::sync::Arc;
  pub fn start(cfg: Config) {
  - let mut router = Router::new();
  let networks = Arc::new(cfg.get_networks().unwrap());
  + // start background thread to refresh sync blocks
  + start_http_server(cfg, networks);
  +}
  +
  +fn start_http_server(cfg: Config, networks: Arc<Networks>) {
  + let mut router = Router::new();
  handlers::block::Handler::new(networks.clone()).route(&mut router);
  handlers::pack::Handler::new(networks.clone()).route(&mut router);
  handlers::epoch::Handler::new(networks.clone()).route(&mut router);
  