makes Hash.getKeysAsHash() rely on .getKeys()
introduces on-demand item count to Collection
introduces on-demand key & item count to Dictionary and StringDictionary
relegates on-demand key counter from Dictionary and Collection to Hash, implicitly renames Collection.count and.getCount() to .keyCount and .getKeyCount() accordingly
version bump
adds clarification fot counter getters in Hash and Dictionary
removes superfluous .getKeys override from Collection