Service constructor.

Instances will contain a map to all of the
services that have been mounted onto the
system.
function Service(name) {
  debug('new service: %s', name);
  assert(name, "service not supplied with name");

  this.name       = name;
  this.middleware = [];
  this.uri        = new Uri();
  this.status     = new Status();

  this.initialize();

  return this;
}