v1.0.0

• Add Add method in order to insert an item to the cache only if an item doesn't already exist for the given key, or if the existing item has expired
• Add Replace method in orde to set a new value for the cache only if the given key already exists, and the existing item has not expired.

v0.1.0

• Return false (rather than error) when key is not found in cache
• Do not return expired item in case it is expired but still in the cache
• Add docs to each function

v0.0.1

update readme