docs: public static <T> T instantiateLowlevel(Class<? extends T> clz) {
      Exception last = null;
      for(Class<?> c : ELKIServiceRegistry.findAllImplementations(clz)) {
        try {
          return clz.cast(c.newInstance());
        }
        catch(Exception e) {
          last = e;
        }
      }
      throw new AbortException("Cannot find a usable implementation of " + clz.toString(), last);
    }