Return names of available generators

		:param family: name of hash-generator family to select
		:param name: name of hash-generator to select (parameter may be used for availability check)

		:return: tuple of str

def available_generators(family=None, name=None):
		""" Return names of available generators

		:param family: name of hash-generator family to select
		:param name: name of hash-generator to select (parameter may be used for availability check)

		:return: tuple of str
		"""
		generators = WHash.__hash_map__.values()

		if family is not None:
			family = family.upper()
			generators = filter(lambda x: x.generator_family() == family, generators)

		if name is not None:
			name = name.upper()
			generators = filter(lambda x: x.generator_name() == name, generators)

		return tuple([x.generator_name() for x in generators])