Some bugfixes in HashCache
FileStorage:
refactoring of __getitem__, __setitem__
added TestCase
written load/save index
added functions: __put_to_index__, __get_from_index__, __save_key_record__, __save_value_record__, __get_key_record__
FileStorage tests works. Not completed
Added test for index on create FileStorage
Beautifying code.
test_fill: append for test FileStorage