Implement metasync.memoize

[tshemsedinov]

Implement functional object with following properties methods and events:

• memoized.clear() - clear cache
• memoized.add(key, value) - add value to cach
• memoized.del(key) - remove value from cach
• memoized.get(key) - returns saved value
• memoized.timeout: Number - cache timout
• memoized.maxSize: Number - maximum cache size in bytes
• memoized.maxCount: Number - maximum cache size in item count
• memoized.on('add', Function)
• memoized.on('del', Function)
• memoized.on('clear', Function)