code: public static <T> Set<T> getRandomSubset(Set<T> set) {
  		return getRandomSubsetMax(set, set.size());
  	}
docs: Generates a subset of <code>set</code>, that contains a random number of
  elements.
  
  @param <T>
  Type of set elements
  @param set
  Basic set for operation
  @return A subset with a random number of elements